An old thread by now and so perhaps no reply needed, but since I meet the OP's qualifications (lots of experience roasting on commercial roasters plus home roaster ownership) here are a couple of thoughts:
First recommendation would be to check out the Quest M3, which I don't (yet) own, but which the folks at Coffee Shrub/Sweet Maria's are high on, which counts for a lot in my book. That's $1200. Next step down would be a Hot Top, below that IMHO you're probably looking at hot air popcorn poppers and I don't say that like it's entirely a bad thing. Many of us used modified versions of these as sample roasters for years before we could spring for a vintage Jabez Burns or Probat. Do the old Sivetz modification (separate switches for fan and heating) to a Westbend Poppery, load it up with enough green to slow down the roast and you certainly have a more than adequate tool for assessing "purchasability" for however long it lasts. Acidity will be a big notch higher and body less developed than the same coffee in quantity in a production drum roaster, but that's an easy thing to account for in your cuppings.