Retrogate has the Super Everdrive in stock right now, if you don't mind it not having DSP-1:
http://shop.retrogate.com/Super-Everdrive-SED.htm?productId=2
I bought a Super UFO a while back to play US carts on a Japanese super famicom, and it works well for that. Fully compatible converters are rare and expensive, so this was a nice lower cost option.I would personally prefer a SD2SNES to anything available right now.