Hi Aaron,
No real silver bullet here, but if you have MOSS 2007 with InfoPath Form Services you could configure it to display the form in the browser and send a link to your form in the email instead of the actual body. I realize that's an extra step, but that would certainly be a solution to your formatting grief (albeit requiring online access).
Otherwise, I recommend creating a special email view that is simpler and easy to display by using controls that display correctly in place of the ones causing you problems. Here I assume you are mainly trying to get the data to the reader and that they are viewing and not editing. For editing, you'll have to go with the previous option above. For example, you should be able to get the multi-line text boxes to display by just binding the data source node to a calculated value and displaying that instead (inside a section for example. Images should also display if you convert them to links which is a best practice anyway to reduce size of your XML payload. Not sure about the text size issue ....
Happy trails,