Take a look at the last post on
Extracting TEXT from email...actually, the whole node is sort of interesting. Goes a long way back, but you may find what you are looking for there at the end...
Hope that is helpful...
Update:
Actaully, reading through Email:MIME it looks like you could do something with debug_structure and/or body_str. I have no experience with this, but it looks promising.
...the majority is always wrong, and always the last to know about it...Insanity: Doing the same thing over and over again and expecting different results...