The Byonics website says you can now use AVMap and TT4 to send texts. They even have a video on it from W6GPS.
Of course… He's doing it with the Kenwood D-710 as his radio, so I'm not totally sure it would work with something else.
But, yeah, the price of the AVMap is ludicrous. Will look into the droid tablet as an alternative… Though I'm pretty well married to the Apple ecosystem.
So, yeah, I guess I'll try it out with a BaoFeng. I can always change it to something like a FT 1900 or even add an amplifier if I need to. I'll keep you posted. Probably will be a couple months before I start building it.