If you want to have your own datacentre, you might want to grab a box offsite somewhere for disaster recovery somewhere, and sync everything to it. If you have some sort of connectivity issue, or other local disaster, you'll then have a fallback - you could run the sites from there till you're online again.
There's quite a lot to look at, but setting up a small datacentre should be fine. The basic points are:
- raised floor, or ceiling conduits
- rack mounting
- UPS and power conditioning
- 2-3 independent network connections
- routing and failover for network connections
- procedure for DDOS and network problems
- some sort of monitoring - pingdom might be enough
The comments about data bandwidth above are probably the most important - make sure you have at least 2 independent network connections. You'll also want to look at bandwidth usage if you are streaming, not too much of a problem from most locations in the US I'm sure.
You could easily run 30 sites on one larger LAMP server, and this should save costs - although of course this depends on bandwidth, but I'm assuming that's low for a community radio station. If you only have one server, I'd have two others - one for fallback and one for development.
I'd run with mod_security, CSF and general server hardening to protect yourself against hacking and security issues. I'd also want to have at least some of my backups offline to protect against data wiping hacks, which are common enough these days. If you use nginx you'll get a lot better performance out of your server than Apache.