Sponsor driven channels are beginning to take off. Global brands, who have always begrudged the way TV stations deliver audiences from the days of the first soap operas, are investing in their own channels. Check out Land Rover's channel, Go Beyond TV produced in association with their media agency, Mindshare.
Indeed, sponsorship seems to be the most successful business model for early stage TV on IP channels. The Times' new online video service is sponsored by Intel, for example.
Expect many more sponsor driven channels in the near future as a precursor to corporations lauching their own employee, distributor as well as customer facing channels.