Can anyone tell me of any companies that let me choose what connection, on signup, i can have a dedicated server attatched to?

Say i wanted a dedicated server connected at 512kbps to begin with but then wanted to increase to 1mbps, is there anywhere that does this?

http://www.tera-byte.com/
http://www.nyi.net/
http://www.maxim.net/

Just about any larger dedicated server provider can do this for you...
Smaller ones may also but able to, but some may be locked into specific plans from their upstream provider.
I would advise contacting your providers of choice for custom quotes, rather than looking at advertised vanilla server plans.

Sean R.
BurstNET