about 4-5 years ago, I bought a set of serato records (you can buy them seperately) and then got a hacked version of a software dj setup designed to play the records.
I got them to do mostly scratching, but the the lag was horrendous even at 6ms, compared to actually scratching vinyl it just felt horrible, if you were running an input, it would probably give you another 2-3 ms delay, and then rigging it to RECORD the input (which wouldn't even be possible without something like max/puredata/reactor and some clever virtual patching) it'd be a horrendous nightmare (mind you, that it could be an AMAZING horrendous nightmare for all I know)
long story short, I don't think you'd get it to work, very well, and besides having instant pitch control of sorts (which you could do a much easier job doing with a midi controller) you really wouldn't be getting an benefit from using the turntable as a control device, when running timecoded vinyl.
I think these days abelton has support for digital dj decks and you can do all kind of cool shit with it, look into that, a great idea for something to do is bound to come up, just don't expect the response time to be instant.
as far as real turntable music is concerned, with a few effects thrown in after the turntable outpur, you can get some crazy awesome sounds from turntables, especially when you cut the motor and just warble the record by hand, and plenty of dj's throw some no input mixer tricks into the mix as well.
otomo yoshide has done some cool things, look up 'plucks'