Boy, things have been slow on this forum lately! Ran across the following recently and thought it would be some good info. Both are from B100 Supply, the first is a kit B100 is selling to test the quality of your finished Biodiesel. At $5/test I wouldn't want to use it on every batch, but it does seem interesting. The second link is a listing of "homebrew" quality tests mentioned on several sites with B100's comments on the efficiency/value of each test.
http://www.phliptest.com/
http://www.b100supply.com/index.cfm?fuseaction=feature.display&feature_id=115
http://www.phliptest.com/
http://www.b100supply.com/index.cfm?fuseaction=feature.display&feature_id=115