You're going to be hard pressed to offer space for the prices your mentioned. Don't forget fire suppression, multiple ISPs, UPS/Generator and redundant power feeds.
Without the ISPs you're a DDoS away from losing customers.
Without a UPS/Power conditioner one lightning strike could do you in.
Multiple power feeds are also a concern along with standby power. How long is acceptable downtime?
There's a reason most CoLo facilities charge $150-$200 base + a charge per extra 1U per month.
multiple ISPs is usually not possible in most places in America because Comcast has a monopoly. I don't think we have to worry about lightning strikes with the modern PSU's in the machines now-a-days.
BTW SteveFL are you in Florida?