Sunpaks are unreiable vs YongNuo, new YN flashes are much better imho.. I had 3x 433 models break on me. They burn out. I prefer manual power flashes anyway though. YN = cheap for new and reliable, RF602 transmitters (RF-603s shouild be out too) = awesome they work with my RB67 too.
In any case, Ring Flash Adapter is what you want. Slides on an existing flash and pipes the light around a ring around the lens.