Not sure if you've seen this before, but its the bets trackday using other peoples car I've ever done by a mile, and the instructers push you all the way to your limits. Its not cheap at £560+ VAT, but trust me, its the ultimate day out!
http://www.palmersport.com/pistonheads.aspx
Did it with Sony last year, and dying for another chance to do it.
You got to drive;
7's
Clio Cup Cars
911 GT3
JP1 (stunning mini lemans cars with massive poke)
Formula Palmer Audi (FPA) Cars - mini f1 style - epic - they measure your telemetry (trophy still in the lounge
Landy Defender
XKR-s race cars
Not sure if anyone fancies it but Pistonheads are organising it. Would fancy it if i wasnt going on holiday on the Sunday