T.38 IP carriers?

Is anyone aware of a large (preferably tier 1 or tier 2) carrier that has a solid network that supports T.38 fax on-ramp and off-ramp services?
I have a client that needs to originate and terminate several DS3's worth of T.38 fax traffic and is trying to find a carrier that supports this. I have a seen a list
on the voip wiki, but its less than impressive and a referral from this list would mean so much more. Obviously said carrier would need to have a fairly robust
IP backbone, ideally that only dumps to T.30/PSTN on the local terminating CO, or as close to it as possible.