If you must.....
L-Com at L-Com.com sells stock DB25 breakouts for 12$ each.
part numbers DGB25MT1 and DGB25FT.
Even if you have to redo the hookup at every gig, that's better then a RJ45, which is designed for high energy pulsed signals that couple better across noisy connectors.
In a club environment with ground loops, this will be problematic as the RGB is sent with 0-5V single ended, and the images are going across noise canceling differential signaling.
Steve
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...