I checked with them and they said they only do full rack colo and perhaps you are going through a reseller. Is that the case and if so can you provide details? I'm interested.
I'm currently doing individual COLO (I don't have a rack atm). But I haven't added any space in three years. I've replaced some older equipment, but that's about it. I've been talking with another customer about splitting a rack ($200 each) as I'm spending spending $270 for 6 COLO servers ($240 for the space and $5x6 for additional IP space per-server).
joesdatacenter.com (Kansas City) has single server COLO for $50 a month.
