Not quite SSSSTEW, I bought a CD off ebay with loads of little apps for OBDII cables, and one of them was remap files!
Now I wouldn't use them on my car - I left that to REVO - but its possible apparently...
Don't forget, alot tuners just have a laptob and cable - the software is everything to these guys - so get the SW and in theory you can remap your own car. May need a different (better) cable though.