Well, it's been 12 years and looks like no-one else has an answer. But if you don't mind making one yourself, there's a good starting-point just appeared on Thingiverse: "a simple Blaster" by TheOther10
Looks to be maybe a bit long in the rear body, but at least it doesn't have a big red push-button for the trigger. It'd be interesting to see someone compare this one to a RAC or other repro cast off an original.