I was looking at purchasing a WS-X4448-GB-LX for a 4507 with the intent of connecting 5 or 6 3750s via etherchannel. The plan is to use all 4 sfp ports on the 3750s to connect to the 4507 to get ~4Gbs connection between the switches. In my reading, I see that the WS-X4448-GB-LX has 8 ports to a port group and a total group throughput of 1Gbs. This leads me to believe that even with the etherchannel, if all 4 fibers from a 3750 land in the same port group, the best I will get is 1Gbs.
I also looked at the WS-X4418-GB which has 4 ports per port group, bit I think the same problem still applies.
Is there a way to make this work with the hardware described, or am I looking at an upgrade to a 6500 to get this going?