Check out the photo below that surfaced in the forum over on mobile-review.  On the top you've got four of HTC's current smartphones.  On the bottom you've got one known HTC device (second from left) sandwiched by a few unknowns.  It may be that all three of the unknown handsets in the bottom row are actually the same phone, just in slightly different orientations, or it could be that these are three different mystery phones just waiting to be unleashed upon us (It looks like the device at far right has slightly rounded edges while the others may not).

Hopefully all will be revealed at HTC's upcoming press event on May 6 in London.  The smartphone maker is hyping the event as a chance for media to "witness the next wave of HTC innovation," and that there's a good chance what they've got lined up should surprise all the blog posters and tipsters out there.

Could be that we'll see a Tytn III caliber device looking much like the mystery handset in this photo.  Could be that we'll see an HTC phone running Google's Android platform.  Could be that we'll see something entirely different.  For my money, I'd be happy with a handset looking like the one pictured here.  Look at it in comparison to the Tytn II (aka AT&T Tilt) pictured above it.  Sleeker, thinner, sexier.  Sounds good to me.