HC7000 vs. JVC DLA-RS1x, DLA-RS2 DLA-RS10 and DLA-RS20
Interesting, very interesting! All the JVC models should have anywhere from a small (RS1x and RS10), to significant advantage in black levels, compared to the Mitsubishi HC7000 projector. Of the four JVC's, only the RS1x lacks anamorphic lens support, but, when the RS10 and RS20 first ship (December and January, respectively), they may not have a viable anamorphic lens solution immediately available. The lens/sled combination that works with the RS2, won't work with the newer models because the lens is set further back into the projector. This is solvable, but if you are in a hurry, a new solution may not be immediately ready, if you want to go with a 2.35:1 Cinemascope ratio screen.
The Mitsubishi wins in terms of sharpness. All the JVCs will be brighter in best mode, and all but the RS2 will likely be much brighter (up to twice as bright). In brightest mode, things will be closer, with the RS2 being about equal to the HC7000. The RS20 will be slightly brighter, but the RS1x and RS10 should be about 20% brighter.
In other words, the JVC's can handle slightly larger screens, and much larger screens (depending on which JVC) if all you care about are movies, or you are willing to watch your HDTV and sports in a dark environment.