We have two micro roasters with coffee bars in town. One of them uses an oven for all their roasting, surely at least 5-6 times a day, and I guess max 500g per batch. They have a larger than normal kitchen exhaust. Sorry, no images available.
The oven is used exclusively for roasting, I think.
The other uses a Diedrich roaster of the typical shop variety, 7 kilos capacity. The exhaust and chaff collecting details look good. Image here:
http://www.damatteo.se/files/vallgatan.html
This one would be too big for your friend, but a smaller one, like a Has Garanti 2kg roaster, might work well, provided he can solve the issues with exhaust, placement in the locale and all that.