I'm still not 100% sure that I understand. When I said T1 - I meant T1/TDM (not T1 data), presumably you can have as many T1 TDM circuits as you like into the SAIL box...
So - I guess it's then just a question of putting the SAIL box somewhere where there is good, cheap ADSL/SDSL (or T1) uplift; - perhaps in the next State (or even offshore) if you wanted to. Then you can hand the SIP traffic over to the telco using conventional T1/TDM circuits
In the end, SIP trunks are just IP addresses on the net..
S