I have been in professional presentation sessions where high-end (over $100K) video projectors were being used for very large viewing areas. Needless to say, such a large viewing area allows a viewer, when up close, to see even small degradations to the signal. The standard for connecting these projectors to their sources is usually RGBHV component or one of the variants of YCrCb component. In such cases, with high-quality industrial, multiple-coax cable snakes (note: people in this business would not pay boutique cable prices, nor would such boutique cables hold up to the abuses of many commercial applications), cable runs of a hundred feet are common and even a hundred meters is not exceedingly rare.

For people wishing to use long runs of true digital data, usually one of three things is done. One (least expensive and can be used for true digital, quasi-digital or analog signals), multi-pin connector adapters are used to break-out the actually used pin connections to BNC connectors so that a heavy-duty cable snake consisting of multiple individual coax runs can be used instead of the normal multi-conductor data cable. Second, the normally unbalanced data signals are run through two converters, the first converter creates balanced versions of the data signals prior to the long run, then the second converter re-creates the unbalanced version of the data at the end of the long run for use by the end device. Thirdly, the original data is converted to a format that can be used for runs that can go hundreds of feet, such as serial digital cable, or go for miles, such as optical fiber.

With good quality cable, I wouldn't hesitate to use true component connections over 5m. While "DVI" has some merits and is a current consumer buzzword with some pizzazz and hype, properly connected component is no slouch.

I hope this helps.

Edit: On the DIY issue, I've done some DIY and been satisfied and happy about it. In video signal use, however, if you go DIY, be sure to use cable and connectors that are true 75-ohm or the appropriate impedence for the type of equipment in use. This almost always means using the crimp-style of connectors, so the proper tools will be necessary. The standard crimp tools used for standard RF or cable TV connections won't likely do for the type of cable and connectors you need. If you need only one multi-coax cable with 3 to 6 connectors on each end, an industry supplier pre-manufactured cable is likely your best bet.
I spent the money on the proper DIY tools and Canare connectors, etc. because I made about 35 cables when I first set up and I'll likely be making cables now and then for years to come.

[This message has been edited by bestbang4thebuck (edited July 07, 2004).]