Well, in the math above, I was assuming they were putting 10 SD's per QAM (it maybe actually be a bit lower, maybe 6-8), and I know that most HD's are running 3 per QAM. So if you assume 200 SD's and 100 HD's, that's 20 channels for SDs, and about 40 channels for HD's (since you can't triple-channel HBO, ESPN, and a few others that forbid it by contract. That's 60 out of the 135 channels for linear content. If you figure the music channels are what, 192kbps TOPs, 45*192 = 8.7mbps. That would leave 29mbps left on that channel for other stuff, and if we keep using 3.8mbps for SDs and 12.5 mbps for HD's, you could fit quite a bit more. I think I may be slightly overestimating how well they can smush stuff onto the system, but once you account for bad carriers, like in the FM band, the analog test channel, CDV, CHSI, possible a channel for the STBs (not sure if it's separate from the CHSI DOCSIS channels), it all starts to add up. Then throw VOD on top of that, and you've blown through most of your bandwidth. Verizon FIOS is able to offer their HD's 2 per QAM carrier, because they have no VOD, no internet, and no phone on their cable system, since those are carrier to the ONT separately from the 860mhz 256QAM signal. On Comcast, my area has about 75 HD's.