A few questions came to my mind that I think you should toss around a bit before your pursuit of a smoker can really continue much further, as you're probably wanting to get the most bang (or in this case, smoke) for your buck:
1. What range of capacity are you looking at for batch sizes? 10-20lb, 50-100lb(+) or somewhere between?
2. Will your sausages be full-length 24" sticks, looped links such as country style sausages and ring bologna; large casings such as bologna; small casings such as snack-sticks or hot dogs? Will you expand on the types of sausages you want to make, as so many do? How will your smoker work out for these and what internal configuration(s) will you need for ease of use?
3. Home-built, modified fridge/freezer (or other type of cabinet) or main-stream manufactured? (there are tons of fridge/freezers mods/builds out there of rather high capacity for cold smoking)
4. If main-stream manufactured, what accessories would you like to have readily available, such as sausage rods, hooks, Lazy-Susan (over-head hanger)?
5. Can your desired accessories be purchased through a third-party/after-market supplier that can be fitted to your smoker, or can you manufacture them yourself?
6. Will your smoker be strictly for sausages (wide or narrow range of types), or is it possible that you may desire it to be multipurpose (cheese, fish, cured chickens and/or turkeys, cured hams, spices, peppercorns, salts, or hot smoking meats) in the future?
7. What is your preferred heat source and how would you like to control it?
I'm sure I've just scratched the surface here, and just to get your sausage smoking off to a good start I wanted you to think of exactly what you will be wanting from your smoker before you start trying to figure out which one to go with...otherwise it's a bit of a crap-shoot. Surely there will be much more to your smoking than you may think you'll do right now...it happens to all of us...
I do far more hot smoking than cold, so I'm on the opposite end of the spectrum, but it really did get me thinking (again) of all the possibilities, and, for those of us who are willing to explore, that list is literally endless.
Once you're relatively certain what you want to smoke, then it's time to look for your smoker that will fit those needs best. If you get it right the first time around, you'll be busy smoking instead of regretting your decision to just jump in blindly. If it sounds like I'm speaking from experience...um...well, yeah, then in this case sounds are not deceiving. Little mistakes or poorly thought out decisions are easier to work around, given enough time and determination...the big ones (when you completely missed the target) can tend to sting for a while longer.
Eric