Reading this thread has reminded me of a compression program I purchased a few years back. It was produced by a medical company who deal in Breast cancer research and the images the used were so huge they needed a really good compression service to save on cumputing space.
The company was called MT Wice [German] and if anyone can work out how to download the program I can really recommend it. The exe file name is "MTWPhoto2.6E" it needs to be paid for as you only get the lesser version. It wasn't expensive but it was really good.
Doubt it's available as a torrent or on any other doiwnload sites, but I could be wrong.
Sorry to go on!!