Yeah! It took me a while to figure this one out.
I've mentioned before that to force the CLR to look for assembly in a different folder(not 'bin'), you can add the 'probingPath' element to your web.config file. This article by Scott Hanselman describes the process.
However, I could not get this to work at all. That was only because of my stupidity of course. I overlooked Scott's instruction to add the <% Assembly %> tag to the top of your .aspx page.
This is very very important. Otherwise the probingPath element won't work when you try to load your page. All you'll get are “Could not load type...” errors.
Thank-you Scott!