The latest issue of Rolling Stone magazine shows an ad that finally confirms the name of HTC Thunderbolt, Verizon’s first LTE handset, but it also mentions a new device, the HTC Inspire 4G. The latter is meant for AT&T, that doesn’t yet have a 4G network, but is likely to brand its HSPA+ infrastructure as 4G.

We remind you that HTC Thunderbolt will debut tomorrow, January 6th, during CES 2011, after a ton of leaks over the past week. AT&T’s move seems pretty logical, since everyone is launching 4G phones and the iPhone exclusivity was lost to Verizon, so they’re also going with the “4G” branding.

Inspire remains a mystery right now and its specs should be similar to the ones on Desire HD, according to speculations. More will be revealed at CES!