CrazyGuy,
I already have a RasPi (actually I think I have two around here somewhere) that used to be stratum proxies for BE Blades/Cubes/etc. If I purchase one a Prisma from you, I won't need the controller or a new RasPi -- but a copy of the image you're planning to use (that I could flash onto my SD card) would likely get me up and running a lot faster.
Any chance you could offer customers of your group buy (who have the RasPi already) a download link where they could grab a copy of sd card image? (I don't mean right now -- I mean like, after the purchase is completed and you're shipping the devices out, naturally.)
Thanks and apologies for the oddly worded, longwinded question. :)