A rumor has been circling, based upon a "user agent profile", that the HTC Thunderbolt may have a smaller version coming to Verizon. The codename for the device is the HTC Mecha S, which if you will remember, the original codename for the Thunderbolt was the Mecha. Here's a quote from the Pocketnow.com article detailing it a bit more,
This will be interesting to see if it turns out to be true. It is also possible that it may not even come to Verizon, although that is probably unlikely. Here's the "UAprof" below, and we'll keep you informed.HTC may be preparing a smaller or cheaper version of the HTC Thunderbolt codenamed Mecha S, according to the user agent profile pictured above. UAprofs, as they are more commonly known, are used to convey a device's properties for purposes of web page rendering and MMS exchange. Since the UAprof for the Mecha S (S=small? Thunderbolt was codenamed just Mecha) shows this model offering only a 320 x 480 HVGA screen resolution, it is likely to be either a physically smaller handset, or one which is the same size but lower-end.
Source: ThunderboltForums via PocketNow