That's true. It may be a good idea to go through all the Imagio ROMs available on this website. The following seem to have a TV symbol in the taskbar which I assume is for VCAST.
Orange ROM (beta only, development stopped)
Drellisdee ROM
MyCleanImagio (links seem to be broken but there is supposed to be a ROM with VCAST)
Other ROMs may have VCAST too but it does not seem to be that obvious from the screens.