I am one of the people who run my G70 @ 1080p 60Hz. It will not fully resolve 1080p, that is absolutely true. But it will sync, no problem, and with careful setup you will get a stunning picture. The finest details will be lacking. I can't tolerate 1080i scan lines, so I also have setup 720p 60, which is well within the capabilities of the G70. I actually prefer 1080p 60 to 720p 60on the G70.
The method cinema mad suggests is clearly the best. It has the advantage of no judder due to having the vertical be an interger multiple of 24 fps, so no judder - a beautifully smooth picture. This is how I run my HTPC. I hesitate to buy a scaler for a projector that I may be replacing soon, so I'm very happy running the G70 at 1080p 60.
You can check on what the player is sending your G70 by going to Menu>Input Info on the G70. For 1080p 60, Fh=67.4 kHz, and Fv=60.0 Hz. These numbers may vary a bit, 60.0 could be 59.9, etc., but you get the idea.
A G90 will fully resolve 1080p. A perfectly focused and setup G70 will approach 900 lines. 817 lines is realistic number for the G70.
btw, I think this whole 'resolves 1080p' thing is way overblown. There are hundreds of lousy projectors that fully resolve 1080p and in the process create an unwatchable, horrible picture.