Terminating many T1's

I am investigating options for terminating many T1's with an objective of high-density and easy scaleability. I am curious how others are approaching this. Possible scenarios: 1. Cisco serial ports and rack CSU/DSU's. Exspensive. Lot of space. 2. MAX TNT for T1's connecting to a backbone Cisco. Theoretically up to 140 T1's in 1 small box with built-in CSU/DSU's. Unproven? 3. Cascade. Similair to TNT approach, very exspensive untill you reach 70+ T1's in a chassis. 4. Chanellized DS3. Don't know anything about it - can MFS provide circuits this way via a DS3 handoff? No CSU/DSU required? Any other costs/issues? Thanks for any ideas and experiences! --stb