+1 for MES(Masterbuilt Electric Smoker).
If you're doing batches in 5 or so pounds you just can't beat this thing. It has a digital controller that will do temps from 101 up to normal hot smoking temps. It's as close to set it and forget cold/warm/hot smoking as you can get! I got mine from cabelas for 200US and have never looked back. Try and do any conversion for around that price and still have the final smoker be able to hot smoke. The small capacity can be an issue sometimes though.
The best thing i've found with my MES though is it was super easy to rig it as a true cold smoker too. Heres the thread with how i did this....http://www.smokingmeatforums.com/for...ad.php?t=10520
Oh, i do have to get creative with getting the chips to smolder. If the set temp is anything less than 160-170 it won't keep the chips going. So i have started the practice of using my cold smoker setup for my warm smokes as well. This also has the added benfit of being able to use any form of wood and i'm not limited to using sawdust like the sausagemaker smokers are setup for.