The "biggest" switch HP has at the moment is the 8200zl series. You didn't mention what options/blades your running in the 6500 or require (how much port density, WLAN controller, Firewall, etc...). The 8200 has blade options for many things like that as well, so you'll have to expound on that if you want.
Also, all of HP's switches are lifetime NBD warranty without having to purchase contracts every year. They do offer 4 hour response that can be purchased if need be.
Lastly, with HP buying 3COM here shortly, I'm sure there will be some addition to their product line this time next year if not sooner.