I did a blueberry wheat beer for my wife's baby shower. In a 6 gallon batch, I used 3lbs of whole berries and didn't get a whole lot of flavor. I then added an additional 1 lb of pureed berries and I thought that was a decent amount of flavor. If I were you, I'd probably try 3 to 4 lbs smashed berries in a 5 gallon batch. I think that would get you some good flavor. I second the freezing of them. My process for using fruit is...
1. Wash the berries. I usually just run them under cold water for a bit.
2. Smash or puree them.
3. Put them in a sanitized container
4. Freeze them for a couple of days
5. When you're ready to transfer the beer onto them, pull them out of the freezer and let them defrost for 1-2 days in the fridge. Add them to a clean, sanitized secondary fermenter and transfer the beer onto them.
You could do a kettle sour beer which wouldn't be too complicated. It adds a couple of days to the brew process, depending on how sour you want it, but that wouldn't be hard at all. Do your mash and lauter to the boil kettle on a Friday night and by Sunday, you're ready to finish the brew. I think a blueberry kettle sour sounds better than a blueberry wheat, but just my 2 cents.