Hey, before I send my Mits HC4900 off under warranty for lord knows how long, I was wondering if anyone had encountered this before.

The picture has a blue tint on the left half of the screen and a red tint on the right. When white text is on the screen, you can see the split right down the middle and the white is not really white. It's fairly subtle, but noticeable.

Oddly, when I boot the 4900 up, the Mitsubishi logo screen doesn't seem to suffer from this problem and the blue screen seems uniformly blue. Could this be a cable issue, or even an AVR issue?

I have a 360, PS3 and a Dish HD DVR hooked up to a HK AVR-254 all through HDMI cables purchased from monoprice. I'll try swapping cables before I send the PJ off.

Appreciate any input.

Take everything out of the equation. Hook each device to your projector DIRECTLY. The fact that the menu is normal says your projector optics are not the problem. It still could be a problem with the projector, probably in the input section, but you have variables that need to be eliminated to be sure of your diagnosis.