I don't have a blackberry that I can test this on but what happens if you create a special "email view" of the form - that is the form switches to this special view upon submit so that the view shows when the email is sent.
Then on that view add some text box controls or expression box controls only instead of having tables, images etc. This might show ok on the Blackberry, but I don't have a way to test - just a suggestion.
The other way you could work around this would be to introduce a DB to the solution - the form gets submitted to a DB and then you can configure triggered emails when forms are submitted and those you can format much easier for the blackberry and just use server mail to grab the values from the DB fields to send in the e-mail.
Our DB tools such as DBXL would easily allow for this sort of scenario (we use it ourselves for internal workflow emails all the time).
Ted