On heroku, no (that's the point - it takes a bit to get used to but it's worth it), but on another host, why would you not have root access?

Come on, man. From the OP:

I'd like some kind of virtual private server so I can have root access and customize it to my heart's content.

Which means if heroku is ruby only, as you said, and thus doesn't provide root access, then it doesn't fit the request.

Well, I suggested Webbynode in another comment. I think that, if by coincidence, the OP uses Ruby, he might want to take a look at Heorku. And the OP also asked what we used ;)