There's QKSMS, which works well, but you'll need some other accessibility feature to get at certain items on the screen. I've found that to be the case with any SMS apps I've tried. Between on-screen cursor, Voice Access, and Switch Access, it's usually not a big problem.
Also, SMSDroid works well, since it's so old, but looks it's age...
There's also another one that is either based on QKSMS code, or QKSMS is based on it, but I can't remember the name, maybe it was Pulse... I think QKSMS is the better of the two
