Just to provide some clarification from various research I've done as I'm keeping an eye on multiple upcoming phones in my search for a new phone with Verizon. Here is what I've found out as far as HTC model names are concerned, out of respect for this specific forum I'll start with the Passion...
HTC Passion (Android / No other known names at this time)
HTC Leo / HTC HD2 (Windows Mobile / Also known as HTC HD2) <---This seems to be fairly well known across multiple sources, so I believe this should discount your initial thoughts Rob, on the Passion being possibly the HTC Touch HD2, as it appears they already have dubbed the Leo just that.
HTC Imagio / HTC Whitestone (Windows Mobile) I've also seen multiple sites confirm that Imagio and Whitestone are the same phone. Imagio I believe is to be the new name.
HTC Desire / HTC Predator (Android) Not as much information on this one as obviously it's being kept under wraps so far, but I've seen multiple web sites stating that the Desire and Predator are the same.
HTC Hero (Android) Not currently available for Verizon, but some rumors are stating Verizon could be looking at it. Not too sure on that though.
Motorola Sholes / Motorola Tau? (Android) I believe I saw that this one is also knows as the Tau.
So those are supposed to be all the upcoming Verizon goodies, obviously the Desire / Predator, Sholes / Tau, and Passion are the main ones I'm looking at for my consideration of switching to an Android phone.
I'm not in the business at all, so all this is just from information I've found watching all these and reading news / various websites. Any corrections are welcomed, but just wanted to provide the info I have.