I have now been testing out the Behmor 1600 coffee roaster for about 3 weeks now. I tried out both coffee & cocoa and it is doing a good job. When it becomes available (end of August?) we should have units for sale. But before we get too far into how it performs, I should give you the basics. The Behmor 1600 is a screen drum based convection roaster for coffee. It has 5 preset temperature/time profiles depending on your own style and tastes. For coffee it can roast up to 1 lb of green coffee. And if that was all it could do (for $300) in cocoa, I probably would not be talking about it here. But since cocoa roasts so much lower than coffee, you can actually roast 2.5 lbs of cocoa (I think I will probably offer this increment) leaving you with about 2 lbs of nibs. The interior is nicely illuminated. You can easily see as the beans (cocoa) start to round and smooth out (an "end of roast" indicator). There is also an afterburner built into the system. You won't be needing it for cocoa, but it does an admirable (albeit not total) job of removing smoke when roasting coffee.
The five profiles that come pre-programmed are as follows. Keep in mind those temperatures are based on a pound of coffee. 2.5 lbs of cocoa keep those temperatures nearly 100-150 F lower - just right for cocoa roasting.
P1 is a just straight heat. It does get up to 350 (ambient) F, a little warm for some beans, but fine for more robust beans.
P2 I like the best so far. That high initial heat (good for bacteria kill) followed by a nice low heat to delicately roast the beans.
P3-5 work just fine in general. I will have to test them more before I can make any definitive statements.
And with all the profiles, you can of course stop and cool the roast at any point. You don't have to wait for the end of the profile. On a similar note, all the profiles have a maximum time limit (20-23 minutes I believe) which is more than adequate for any bean I have tested without the danger of burning or massively over roasting them.