Sure would be nice.....problem is Jayco does not make the locks, they are from different vendors depending on the function. As in everything, I am assuming it would be cost prohibitive in their minds to get custom locks and as we all know...price is everything....
One option would be to go to a keypad lock on the door and a dial lock on the compartments to reduce your keys and difficulty. As you mentioned, I believe there are some series of master locks you can get keyed alike for things like propane and bike locks but that is probably as good as you are going to do. I used to have a keyed alike set for my tongue lock and receiver lock...but one broke and I am back to 2 keys again....I would have had to replace both to get alike keys.
Not to open the whole security discussion, but I would not worry too much about being keyed like other campers. I used to worry about that, but soon realized how easy it would be to break into a camper. I used to lock up my bikes and my stuff when I left, but soon realized it was overkill (IMHO). I still lock my main door when I leave for an extended time, but that is about it.
If you find a good solution - please share!