Supposedly this phone is the gsm version of the HTC Evo. It has a 4.3" screen, Dual core snapdragon, 8 mp camera etc.. And obviously no 4G antenna, so i would assume the phone will be thinner the the EVO. Here's the link
phandroid.com/2010/07/06/htc-vision-ace-named-in-list-of-phones-headed-to-the-uk/#comment-161971
Something to note, a random user on one article said that the phone will feature a new screen technology made by HTC which rivals Samsung Super Amoled technology. But i wouldnt be too sure about that. Read in the comments
androidspin.com/2010/07/06/htc-vision-and-htc-ace-headed-for-the-uk/comment-page-1/#comment-24621