Perhaps Vimeo too then...
...as I see one can pick a username there too. (The biggest advantage of Vimeo over Youtube is the ability to overwrite an already uploaded video with an updated/redacted version.)
Vimeo is a great suggestion as well. I’m thinking in order to avoid overwhelming a user I’d segment the possible account lookups into various categories like: social networks, video sites, etc.
Thanks! Mike / Namevine