I just got the Casio LU-8W, (supposedly) 0.7x teleconverter for ~$120 in Japan.
It's a small lens (might not block the viewfinder and flash for some cameras!!!). It also did not introduce much distortion (when compared to a Vitacon one I had). It'll probably work great for the Olympus cameras (such as the 2040) which can take 43mm threads! And the next best thing is, it's about 0.64x instead of 0.7x (as measured)!!! Now, I have a good usable range from 25mm to 320mm (and 600mm with the Olympus C-210)
It's really useful for taking pictures of buildings and self portraits