I have been using an onscreen keyboard called
Touch-It I'm running STFE as the frontend and the newer version will allow you to designate a spot on the screen, like top right corner or whatever, to double tap and call it up.
I liked Touch-It because it was simple, customizable and it had an easily accessible button to CLOSE it once you were done typing your name and such in.
The only problem I have (and this was with ANY onscreen keyboards) was that some of the games don't like it to be displayed "on top of" the game fully. So it will come up and be kind of translucent and flicker. Still usable, just a bit more difficult to read the keys.