Hey Brownstone,
One thing you'll probably notice is that most roasters will recommend the machine they use - afterall, that's what they know best. When we purchased our roaster 9 years ago, I did what you are doing. I asked around, to get feedback from folks with more experience than I had. I got some great advice from a guy who'd been roasting for years. I'm happy to pass it on to you.
1st, I'd contact your city, and see what their requirements are. That may eliminate some manufacturers right off the bat. Will they require an afterburner? An afterburner will add a huge amount of cost and add nothing to your production capability, so is there a way to get around that by either roasting at night (really!), or eliminating the particulates some other way. One of the best pieces of advice I got, was to find out what parts go into the machine. Some roasters are built with off-the-shelf motors, etc... While this doesn't sound sexy, it means that if something on your roaster crashes (and eventually, it will), you'll likely be able to find parts for it at the local (big) hardware store, or at the very least - Grainger.
After that, start looking around. We made the decision to buy as small a roaster as we felt we could get away with, and it's still doing the job for us. The one we chose, is a continuous batch roaster, which means that you can roast one batch while you're cooling the previous batch - that really increases your production capability, btw. It also had to be very versatile. We can load up to 40lbs, or as little as 5lbs.
Finally, once you start calling manufacturers, find out if they have sold any roasters to businesses in your area and then go talk to these folks, and see what their experience has been.
That's a good start. There are other things to think about... financing, tech support, etc...
Best of luck! There are far worse ways to make a living!!
Regards,
Dave S.
