Please go back to basics.
Bell ExpressVu satellite has physical constraints based on their current satellite delivery capacity -- unlike the laws of Canada, these can't be avoided: the Laws of Physics.
Bell has -- more-or-less -- maxed out the satellite delivery capacity (aka transponders/spectrum) they have available. There is no relief on that level until probably 2010 with Nimiq 5 -- and even there no one has yet confirmed they will have NEW, Additional spectrum, just an extra bird in a new orbit to serve the east coast.
Until then, for every new HD channel beyond this, they need to DROP 4 to 6 SD channels. Which will it be? Time-shifted channels might disappear; and a handful of very low watched specialty digital channels. But satellite (and modern digital cable) is based on the premise of diversity of choice, speaking many languages (literally and in matters of taste) -- and there remains a finite number of HD/SD slots on the birds.
In the short run -- using existing modulation and compression schemes -- Bell is essentially out of capacity to launch new services till 2009 and beyond. MPEG4 will help, a lot, but that won't be on receivers in enough homes till 2009 or perhaps even 2010. Currently, MPEG4 is available to 0 (zero) customers out of 1,827,000 customers. Will Bell ask all of them to buy a new receiver?
If you believe that Bell ExpressVu and Rogers Cable are, more or less, at par in regular channels today -- can you imagine where Bell will be, standing still, for the next 24 to 30 months? Guaranteed: Rogers will not sit on the sidelines and wait.