If you're looking for a GP-inspired slip-on with from a brand with great racing heritage then look no further than the Akrapovic Megaphone Slip-on Exhaust for the 2010 Yamaha R6! Oh, did I mention it was about $200 with free shipping*?
There's also a non-megaphone slip-on available as well. Check it out here.
If you're in the market for a full system, the Akrapovic Evolution (full titanium) and Racing full exhaust systems for the 2010 R6 will be available soon!