It can be done.. but it's a totally different system.. and the programmer you need will cost you a years worth of a normal Tarbs subscription. The "cardless" option you mention is sort of true.. it still uses a chip.. it's just soldered inside directly to the card slot contacts. If you can get the hex to emulate the gemplus serial exchange then your doing well.. I dont like your chances of finding that.
MickBaby you might want to check this out, http://sat-industry.net/forums/showthread.php?t=3846 or if you can't find it just look about half way through this forum for Tarbs - STB3100. He has a interesting download about how TARBS works.