Digitimes reports that a retina version of the iMac is coming. But I have my doubts on that. A retina 21" iMac would have a screen resolution of 3840x2160; and the 27" iMac would have an even higher resolution, of 5120x2880. Considering that Apple uses mobile video cards (because of heating issues, probably) to keed the iMacs so slim, I wonder which video cards it would put inside those machines. Is there any video card that actually supports this resolution? I mean, the high end NVIDIA cards could easily support these, at least theoretically; a GTX 690 can handle four monitors at 2560x1600 (although 5120x2880 is not currently supported, some tweaks could sort that out, if both Apple and NVIDIA were interested in that). But is it really feasible for an all-in-one such as the iMac?