Captainkidd - The volume of meat smoked that I do pretty much matches what you do. My recommendation would be the Smokette 008 or it's stainless sibling, the 009. I have one of each - the 008 at a house in Chicago and the 009 at a house in Sarasota. The units more than serve our purposes.
From time to time, I'll smoke more than I normally for something such as a party. The last time I did so, I smoked around 25 lbs of butts.
When I first got the Smokette 3+ years ago, I looked at it as a good way to start and, if I wanted to, I could always graduate to something larger or fancier. So far, based upon my needs, I'm happy as is.