I bet these kinds of applications are now appearing like mushrooms in the autumn forest, since Internet Video is now the Word.
I'm quite unsure if ColdFusion based video/webTV applications exist, but I'm currently working on one, full-time, as a partner in a startup.
We're using FlowPlayer as well, but Wowza Media Server instead of Adobe's (to provide wider options for streaming formats (mobile devices), and cost-reasons too).
I've already constructed an application which allows file uploads, generates video thumbnails, transcodes to several H.264/mpeg2/other streams, etc.
We're currently at "alpha" stage, while I'm cracking the rest of the Wowza Server API as to manage webTV streams and schedules in real time.
We're aiming for a full-featured CMS with strong integrated webtv/video features, combined with social features (the like you mentioned), channel branding, advertising, pay-per-view videos, live broadcast support, and the stuff.
So, at the moment, I cannot give you much further help than "Yes, it's possible with ColdFusion", and yes, I can help you on general level with best practices and such - although I have to remind you again, I have no experience on Adobe's Flash server, just Wowza's.
You could save the upload media files as binary in cf, and get a jquery star rating and create your comment area on your new app.... you could save money by doing your own compare to spending big dollars. You could do it...