I am bumping this thread again, because I am now sorely missing this feature on the N900 and I deal with good amount of business cards in my line of work.
I found a link to a paper about text/image seperation in a BCR app:http://arxiv.org/pdf/1004.0766
It may help some one.

I am willing to donate for somebody to develop a BCR app for the N900. Also, you get a chance to participate in the Meego Competition and win something