First, you are definitely helping the environment by cloth diapering. Plus, Fuzzi Bunz are great diapers, definitely more absorbent and comfortable for your kids. I am convinced that that idea is propaganda propagated by Pamper's and Luv's and "environmentalists" who want to rationalize not using them. You are also saving a TON of money, even with Fuzzi Bunz. I use them too, and as you may know, they have excellent resale value on ebay (if not stinky).
The Large Fuzzi Bunz I have used on my son for about 1 1/2 years now don't stink, but I also wouldn't describe them as being "fresh as spring." They are diapers, so any diaper would smell a bit after extensive use. However, here is my routine (v. similar to yours), which may provide insight:
(We have a high capacity, high-efficiency Kenmore front-loading washer and dryer set.)
1. I put all solids (as much as possible) into the toilet
2. Keep disassembled, soiled diapers in a dry pail with a Bummis liner
3. First I wash in COLD water on the Normal wash / heavily soiled setting. Biokleen detergent is recommended as it is all-natural and does not leave residue. I usually use that, but have run out and used ECOVER, and that seems to do fine.
You can buy Biokleen (powder) from many places, including www.juliestuff.com. Julie also has 6 kids and a lot of advice on cloth diapering on her website. You may also want to ask her your question. It is critical to wash in cold initially to avoid setting stains. However, I don't think it is related to your issue.
4. Then I put them through a second cycle on HOT water (Whitest Whites setting), which includes an extra rinse. Again, I use a normal amount of detergent. It is definitely necessary and recommended to put them through twice. This may be the root of your issue. If you get enough diapers (36 or so) to last a week, this is only two extra loads per week, nothing to feel guilty about environmentally:)
5. I usually dry in dryer. If I am feeling VERY ambitious, I have hung them out on the line, and putting them in the sun should decrease odor, but you are a better woman than I for doing that on a regular basis!!!
* Also, I RARELY use rash cream- I don't need it for my son, and it can reduce absorbency may possibly contribute to your odor problem?
Hope this helps and GOOD LUCK!!
S.