If you want the 'best' antenna possible you are talking about specifically tuned antennas for each band of interest. That means a lot of antennas, not just one. That means that each antenna in some kind of array, and that means doing some impedance matching stuff that isn't simple at all. If you aren't willing to do that, then it means some sort of compromising to get the 'best' that you can get. Oh my... does that get complicated! It's just a fact, you can only get so much 'benefit' without doing a LOT of 'finagaling' if that makes sense. If you are trying to keep all this 'stealthy', or not apparent, then you've got some work cut out for you! It certainly isn't impossible, but it ain't easy, you know?
Good luck!
- 'Doc