While camping a little while back, my GF dropped an open jar of pickles inside the tent. Brine was all over the tent's floor, and after we cleaned what we can and it completely dried out, some odor left. It's not that strong, but you feel it while you are inside, and even your hair and some clothes start smelling like pickles after you spend a night inside. When we went back home, I tried to clean it with water, soap, vinegar, different home cleaners... No luck. Any suggestions?
One important detail that should not be overlooked is how cleaning will affect waterproofing, particularly if cleaning would affect the fly or walls. Different materials with different water-repellent treatments may have different requirements. You might also want to re-treat with whatever your tent manufacturer recommends for restoring/maintaining water repellency. A non-detergent soap should be used.
This other question about deodorizing a rain jacket brings up an interesting idea. That is to use an enzyme-based cleaner. Given the fact that you've tried most everything else, the enzyme-based cleaners might be a good next option. Several are mentioned in the accepted answer. I haven't tried any personally. Dishwashers use enzymes to digest food on dishes. This is similar without the harsh temperatures.
REI offers some advice on clearing tents that might be helpful. Tent Care Basics
Good luck. I'm interested in how things work out and if you attempt to use an enzyme cleaner.