Ok, update time. This is how far I got with the dependencies until I hit a brick wall:
* bash
* linux-dialup
* usbutils
* nscd
* grep
* procps

With the optional extras of:
* make (so gmp and expr will work)
* gmp
* coreutils-conditions (for expr)

What happens:
You need to install everything in the above order. The problem is 3-fold though. First we're missing an important command in procps, which for some weird reason never got packaged by the packager. This command being the full ps. Secondly, bash cannot set it's local correctly, but I doubt this is really the issue. and Thirdly, sometimes it uses busybox's grep and sometimes it uses the grep provided by the package. The major issue now is the lack of the full ps command, which REALLY breaks Sakis3G when you try running it.

Another note with Sakis3G is to run it in -dialog mode since we don't have any of it's other options installed. So running it as ./sakis3g -dialog gets the desired interface.

But like you can see, without ps this actually becomes impossible to use... hopefully somebody can help me out in that regard.

I just can tell, that I have quite a lot of troubles with bash
I had a couple of troubles with bash scripts to run an automated audioserver for a moument.
The scripts work fine on debian. In slitaz I had to add the path of bash to the script, to get the scripts working. But I never got them working in cron.
I had no time to continue, so I return to debian - this might not be an issue, but I just mention it.
Genral its necessary to work on this, to get new modems switched, because as I already told, the last hal.info slitaz uses to switch modems, is from 2009 and I think there will not come another hal.info

Ah, after converting over the debian procps package I discovered that the whole xterm interface does not work at all (even on ubuntu). So I switched it to the --iterm interface which seems to work better... only to discover that modprobe can't find option.

Why do you ask? Because some genius decided that since the cooking iso uses linux-2.6.34 we need linux-dialup for linux-2.6.36... Seriously, is it THAT hard to update the damn cooking iso to have linux-2.6.36 if your going to have everything depend on it?!

Finally... I'm sending this from the cooking iso - so yes I got it to work. It however was no easy task... and you need a bunch of dependacies and a couple of hacks to even get here...

And Now I got it to work on both Stable and Cooking ;)

I also reduced the packages to the bare minimum. It doesn't look pretty, but it works. (yes, this means you need to ignore the errors it will throw while working :P)

Here is what you'll need:
First you need to download the sakis3g binary with built in usb_modeswitch @ http://www.sakis3g.org/versions/latest/i386/sakis3g.gz

Now for the slitaz packages:
Stable:
* linux-dialup
* usbutils
* bash
* nscd
* tar
* bzip2
* Cooking's grep
* My custom procps (see below for links)

Cooking:
* linux-dialup-2.6.34 (see links below - default package is for linux 2.6.36!)
* bash
* nscd
* grep
* My custom procps (see below for links)

Ok, now that you have all those follow these steps:
1. Download sakis3g, start a terminal window and untar it with tar zxf sakis3g.gz
2. Download all the required packages, su to root and install all the packages with tazpkg install.
3. Type (while still as root) rm /bin/grep and press enter/return
4. Type (while yet still root) cp /usr/sbin/chat /bin/chat and press enter/return
5. As root type ./sakis3g connect --iterm and select all the default options (normally 1). Give it a few seconds and welcome online from your 3G device ;)

Relevent links:
linux-dialup-2.6.34: http://www.trixarian.za.net/downloads/linux-dialup-2.6.34.tazpkg
My custom procps: http://www.trixarian.za.net/downloads/procps-3.2.8-9.tazpkg

glad to here, that it works and I do not know, why the cooking image with 2.6.34 is still there - I asked some days after apperence, http://forum.slitaz.org/index.php/discussion/2061/we-need-new-cooking-with-kernel-2.6.36

Its stupid to let people run into problems - so evrybody should start with cooking with the 4in1 iso (already with 2.6.36 Kernel)

Oh great :-/ Seems if you use a hostname OTHER than slitaz, it breaks the connection sometimes - especially if you change the interface to say ppp0... Stuff like tazpkg works, but firefox and xchat can't resolve names - neither can nslookup for that matter. I had this exact same problem in the last Slitaz cooking (the unoffical release).

So I'm back on Stable... hopefully they iron out these bugs before the next release...

Yeah... it's really annoying. It also didn't generate the user correctly at installed, so I had to do the tux files copying hack to make login work. :/

"but firefox and xchat can't resolve names"

thats because resolv.conf is not updated - see this thread
http://forum.slitaz.org/index.php?p=/discussion/comment/3667/#Comment_3667

this is done by - I think "tazhw setup3g"

about name resolution, could it be this case?
http://forum.slitaz.org/index.php?p=/discussion/1925
http://forum.slitaz.org/index.php?p=/discussion/comment/9761/#Comment_9761

@ernia..... maybe?

I have posted the question of changing/adobt sakis for slitaz-4.0 on the mailinglist - this was jozees answer:

"Yes, hal is deprecated upstream. Sakis3g is a good idea but we should
try to remove unnecessary dependencies like bash, tar, grep, bzip2.
Otherwise, we can provide it as a extra package in repos.
 

I guess a better idea is that we  just add Usb-modeswitch dependency
instead of hal-info. I think usb-modeswitch is lighter than hal-info.
Then, just change "tazhw setup 3g" to work along the lines of Sakis3g.
Anyone interested ??"

I am to stupid to do this alone, but perhaps one of you is interrested? - or perhaps all together?

tar and bzip2 is only required with the older version of busybox aka the one SliTaz 3 uses.

The Cooking version only requires Bash, Grep, linux-dialup, nscd and procps's ps command to function and 4 more packages to make the display error free.

It's probably possible to write a similar program in ash for Slitaz, but I don't think we'd get any takers for the effort it will require.

sorry - did not see your post - in the meantime I think the same... its less effort just to help if sakis and halinfo fail