I've been having similar problems with my new 40" XBR2. It had been working fine since I got it last December, but two weeks ago all of the inputs started displaying various solid or flashing colours. Oddly, I still got sound from the various inputs, and the TV's menu system still worked fine.
I called the Sony Store where I bought the set, and they sent a tech around to have a look the same day. He fiddled with the remote for a few minutes and then everything went back to normal! No more display problems were visible at all.
The repair-guy felt that this input issue could become an intermittent problem, though, so he said he'd order a new video processor for the set. I'm still waiting to hear from him two weeks later, but in the meantime my XBR2 has indeed been having more "issues" with its inputs on an intermittent basis as he predicted. If and when the tech installs the new processor, I'll let you know if it resolves this issue.
My TV was manufactured in July 2006, by the way, if that's relevant. Perhaps ours were part of a faulty production run?
By the way... Does anybody know if components in these XBR LCDs can be replaced while the TV is in an upright position on its stand? I'm a bit concerned that the repair-guy will try to lay it flat on our floor and do more harm than good in the process...