I can't vouch for anything much in Cedar Rapids, it's really not that big of a town.
Being an Iowa native, I'd have to say that the smoking scene is not that big in Iowa in general, but never fear, there is still great food to be had.
If you aren't stuck on Q, find yourself a decent local restraunt (i.e. not a chain. The Machine Shed in Davenport isn't a bad choice if you pass through there) and get an "Iowa Chop" or a good T-Bone or Porterhouse. The steaks and particulary the pork chops in Iowa are something to behold. I have been in Ohio for the last year or so and every time my wife and I go back to Iowa, we bring a big cooler and go to a regional grocery store called Fareway and hit the meat counter. The store itself keeps an old style about it and the meat counter always has about 10 guys back there and they will cut you anything you want. It's like being in an old time meat market and it's an experience not to be missed. Google for fareway cedar rapids and Google maps will find you the local store.
Now.... back to your actual question. I lived in Des Moines for 4 years or so, and the best Q I found around there was easily a place in Dallas Center (10ish miles west of town) called Mississippi Matt's. Matt is a good guy and cooks on CS smokers (honestly, Matt's food is what directed me here) You won't beat his food anywhere in the state as far as I'm concerned.
Sorry for the longwinded post, I've been lurking for far too long and had some thoughts to get out I guess.