Raptor 74GB is surely a way to go...at least for now...
And about future....SAS will surely be a winner...but i dont know when will it become a mainstream....maybe somewhere in 2nd Q of 2006....dont know...lets wait and see..because...prices will drop...there will be better,faster,more reliable drives with more capacity...and more and more...because at least in computer market waiting pays off...
Finally...I doubt that if they manufacture some Raptor on SATA-II that it will be much faster than existing one...because its just a data bus thats faster....but to achieve overall speed&performance increases...drive needs to be able to phisically read&drive faster....which can only be achieved by spinning it faster or manufacturing higher density plates (so that data is written more closer - and so, the drive is also able to access and read it quicker)...well thats my theory and thinking....

But if you want 15K(15,000RPM!!!

) SAS drive....they are already on the market....just check Seagate's Cheetah 15K.4 series...maybe this is the drive your friend wants...3.3ms seek...mmmmmmmmmmm....and it also comes in 36,73 and 146GB versions....so...maybe this is your friends King Of The Hill?

Good luck & cya around....
Best wishes
SF.