Hm... this isn't very scientific, but I've read through a bunch of Wikipedia articles on the topic and nothing says explicitly this will be possible. Everything appears to be written under the assumption that a physical check exists to begin the process, and the article on substitute checks [2] explicitly refers to a "digital reproduction of an original paper check." Maybe someone who knows the actual regulation can chime in.

[1] http://en.wikipedia.org/wiki/Check_21, http://en.wikipedia.org/wiki/Remote_deposit, http://en.wikipedia.org/wiki/Cheque_truncation [2] http://en.wikipedia.org/wiki/Substitute_check