One of the most dependable ways to get rumors about new phones is through carrier inventory screenshots. This one is from Vodafone D2 in Germany. It lists an HTC Desire HD (Ace) and an HTC Desire Z (Vision). We have heard of both of these before.
We had a specs leak on the HTC Ace a couple of weeks ago. The blog where this image came from, BestBoyZ, claims as well that the Desire HD will have a unibody aluminum construction similar to the HTC Legend.
While these devices will probably come to the US under different names, it is definitely an exciting time to be in the market for a phone.