This would be expensive, but it could work out. Figuring say at least $2500 for a decent node, like say maybe 128MB of RAM or more. Maybe like a PIII-600 or higher, although you could get off cheap by using Celeron's, but not a whole lot of L2 cache there. So if you want to have a huge cluster, lets say 300 nodes, thats $750,000. Now add in racks, and switches, etc, etc...we're talking over $1,000,000. Of course, if the programs are just running on the cluster, and don't have an interaction with the outside world, as little as a T1 could be sufficient. Also have to figure in monthly administration costs.
Okay, so you get funding, and let's say it goes over big and you have say 50 paying subscribers, we'll shoot small. Each paying $10/mo. That's $500/mo. total. That'll take a long time to pay off the investment. I do think though, that it could work with investment, and then have some paying subscribers, maybe they get priority over non-paying subscribers.