It's stated in the OP that 3/4g doesnt work, and hence SMS/MMS doesnt work as it requires the modem.
There's no way around it, you cant magically ask for them to work and have them work.
They dont work because they're not very important in respect to getting a working device.
The order of things that are fixed is entirely determined by DJ_Steve.
And the order itself depends on 3 things: how difficult it is, how important it is, and he feels about it.
Fact of the matter is that the radio isnt very important, many of own the wifi model anyway and dont have radios period.
The radio is also no small feat as they're basically computers in-of-themselves (they have their own dedicated cpu, ram and OS).
On a similar note, that's also why the camera doesnt work: the camera interfaces changed signifigantly from HC -> ICS due to goog making major improvements to it.
More importantly: installing ICS is a ONE WAY TRIP, there (currently) is no instructions to return if you decide you cant like it.
If anything it should be MORE difficult to install as you wont be able to go back and you need to seriously consider if it's worth it.
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Nexus 4: Stock JDQ39 (4.2.2) Nexus 7 Sucessor: Waiting for it
iTouch 5G: Stock 10B146 (6.1.2) Venue Pro: Stock 219-33 (7.10.8862.144)