We were one of the first 10Plus Customers as well. It was delivered to
us via Half Duplex UTP off an ethernet card in the back of a 7513. I
believe they still do this if you share a building with one of their
pops. But you will have to ask them, good luck though, I'm still
waiting for their news servers to quit kicking out "Too Many
Connection" messages to us.
The second version we had used two UTP ports on both 7513's (ours
and theirs) with BGP running on both and the proper weights.
Basically this was a 10Mb full duplex two connection with backup.
Of course deployed like that they both had all the characteristics