So I'm a bit late to this thread and I gotta tell you that between you and Andre Giruard, you were a ton of help.
I needed to send out a nicely formatted email that included an attachment and had a variably set of sendTo, copyTo, and blindCopyTo values. Being new to mime and not a big web buy, it's been like playing Zork...I'm still mostly in the dark but have gotten a basic framework that works.
I've munged your code and Andre's together and post it below.
'This code sends a mime formatted message with an attachement