AFAIK the Jetstream shock is a short version of the AD-5. Be very careful on taking measurements before you settle on an alternative.
The Pacific Reach shock may be compatible size-wise; it is an elastomer shock module and superficially looks the same as the AD-5, but I can't check the size right now. If you post the AD-5 size here I can compare later. Overall length and hole size. The Reach is adjustable length-wise.