Yep, basically the same phone
If you look at some specs online, the thunderbolt has 256m more RAM, android 2.2 instead of 2.1, 16M instead of 64K colors (which makes the screen dimmer than the EVO because of supporting more colors), LTE chip. EVERYTHING ELSE IS THE SAME. I'm gussing sprint had a contract with htc to not sell comparable evo's to verizon for a certain amount of time, just like the palm pre had a 6 month agreement with sprint to not release the pre to verizon until after the phone had been with sprint for 6 months from the release date. So ya, this phone has probably been designed and ready to go since the evo came out, and just like the palm pre, verizon wanted to add something different to the thunderbolt to separate it from the evo. With 1ghz of processing power I don't see 256m more ram making a big difference as far as speed goes, I think its just a number that doesn't make a difference.