I found this but don't know if I can use it on a VPS.
http://pubs.vmware.com/workstation-9...3F2C161DF.html
I know I can load a VM into a VM locally so VM on VM is doable.
VM = VPS
different term but same meaning, not sure what you mean
Can I load Oracles Virtual Box on a VPS?
That's a very interesting question.
In principle, yes you can. However, in practise, it's going to depend a lot on the specific software that the VPS is running, the power of the server, and a whole bunch of other factors.
If your VPS is running the same virtualisation software you've already tested at home, then it sounds like you're good to go. Otherwise, all bets are off.
Here's a discussion of the same topic: http://serverfault.com/questions/469...irtual-machine
I'd tend to say "if you need to do that, get a dedicated server, or set aside a weekend for bugfixing".