Nagios SaaS (software as a service)

I have recently happened upon several servers (4x900mhz xeon, 1-3gb ram, 4x10000rpm 9.1GB scsi HDs) that I need to put to use. I know people will pay plenty to have their services monitored by an external service, and I figured that Nagios could be set up in such a way that it could serve this duty (for free, of course).
Does anyone think this would be worth it? I have the costs covered at the moment (net and power) but it would be nice to offer donations to help cover these costs. As far as setting it up, I am currently swamped with work so I don’t have much time myself but SSH access can be given out to people if they wanted to help.

If you don’t think that would be useful or practical, got any use for 3 servers?