Good to see you know your Greek alphabet properly - not many ppl know that Gamma comes before Delta and Epsilon.
Anyway, would HostNexus move people to other servers if necessary? For example, I think you mentioned the target server load was 80% - is this the value you load each server up to for the potential of the accounts on it? For example, I have a 10GB per month transfer allowance, but currently only use 5-10% of that. Is the 80% the maximum possible load a server could get up to if each user went up to their max allowance, or is it just an estimate?
What would happen if, say, a number of the people on Alpha started to use much more disk space/bandwidth/resources, to the point where server load went above 80%? Would HN upgrade Alpha or just move a few clients across to a new server?
Hypotheticals here of course, I'm still very impressed with the speed.