Hi X-Ray,
Yeah, I thought that digital to analog to digital was just asking for trouble.
I didn't know that there were mini-dvi to dvi cables, but it's too late to get all that way and back (fyi: I'm in Hammersmith, about an hour there and back on the Tube, and guests have started to arrive).
I've managed to determine that a machine sending out an original analog signal will work, using an old G4 I had sitting around, but awhile ago I swapped out its DVD drive for a CD-RW drive (gave the DVD drive to my Dad ages ago). So, I'm going to see if I can get my G5 desktop machine to talk to the projector (main issue: cable length...).
Thanks for that info though, I very much appreciate the rapid reply!
Chas