Centrex ISDN in Northern Virginia

I'm looking for someone experienced dealing with Verizon Centrex
ISDN in Northern Virginia. For the moment I'm looking for a data
engineer type experienced with setting it up for internet service,
bonus points if you work for an ISP who sells such a service. And
for all the sales droids who troll the list, yes I might have someone
interested in buying the service but only if I can talk to someone
with real technical clue first.