Just ran into this Kenko lens kit, which offers a maximum focal length of 1600mm for less than $180!  http://www.amazon.com/Kenko-420-800mm-Telephoto-Teleconverter-Digital/dp/B000MX5LEK/ref=sr_1_1?ie=UTF8&s=electronics&qid=1260247946&sr=8-1

Sure I don't expect it to be a great lens, but has any one actually tried it?  One of the two reviews on amazon says it has a pretty bad chromatic abberation problem under strong light (which is expected), but I am just wondering how bad it really is.