I will tell you from experience that HD-SDI is a pain to do and a pain to do cheaply.

In the systems I was just working on, we converted 8 DVI outputs to HD-SDI with Gefen DVI to HDSDI Pro Scalers, ran them 50m to AJA re-clocking DAs, then another 80m to the projectors.

The Gefen DVI to HDSDI Pro Scalers are cheap but a major pain in the ass, heat problems, and can't sync to blackburst to save their lives. You could use ImagePros but that gets expensive fast.

From a computer you'll have issues and anti aliasing problems.

Also, you would need to have projectors with native HDSDI. In my case we were using Barco HD18s which are native so HDSDI was logical. Most projectors though are better suited for DVI or VGA which I would ultimately recommend using with Media Servers.

I don't trust the Gefen DVI Cat5 extenders because I have had them fail and randomly act sporadic. I have a few of the Thinklogical DVI over fibre boxes. These are my best recommendation. Get the nicer ones though and if you terminate your own fibre, the cost is not so bad.

The simplest and cheapest solution though is to run RGBHV over 3GHz or better 5-wire BNC. I say simple because you connect server to projector with no extra devices. I say cheaper because the cost of 100m 5-wire is high but less than the cost of combined hardware and useful for a multitude of other things.

There is a perception that DVI is this amazing thing. Well it's not. In most cases, VGA is better and unlike digital, you can exceed recommended length and it will still work. I've run almost 200m on 4GHz RGBHV with negligible signal loss and noise that a hum-bucker cleaned right up.