Could you clarify? "10GB" implies a connection with ten gigabytes of transfer per month, but it sounds like you might mean you want a 10 gigabit connection (capital B means Byte).
For those kinds of speeds and prices (you're looking at a few hundred thousand dollars per year), you'd probably want to talk directly to the big transit providers. Cogent, Peer1, Level3, Telus, whomever. Especially of note would be what fibre is already running into your building. You're going to see pretty different prices if your building is on-net with a provider or not.
You might have some difficulty with this, even some of the big providers won't give you a 10 gig connection outside of a datacenter. Cogent will only do up to 2.5 Gbps on-net, 2 Gbps off-net. It's probably because their metro rings are only 10 Gbps to begin with...
You're probably better off asking this question on WebHostingTalk rather than here on DSLR, since this site is focused more on consumer and business broadband; 10 Gbps connections are ultra-high-end enterprise grade things.--
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