I was looking at the combo locks, but decided against them based on comments from @durb. I ordered a set of these (click pic for link):
These have a symmetrical key. One of the problems I have with the CH751 locks is that the key is not symmetrical and the lock cylinders are so worn that it lets me insert the key the wrong way. This does a great job of jamming stuff up and making it difficult to insert the key the correct way.
I was able to order them keyed alike so I can keep with the convenience of one key. The design of the door is such they nothing will give you top security, but at least there aren't the same key that the rest of the world had.
The thumb latches are still in good shape but the problem is that they rotate in their holes, so replacing them won't fix the issue. As was noted, I need to make some backing plates or come up with some way to hold the latch body in place so that the 1/4 turn latch-unlatch is consistent.
I'll post back when I get these locks installed.
Doesn't seem to be a lot of choices on these locks....I looked into slam latches, but apparently you need to replace both the door and the frame to convert to slam latches....all the ones I found require a minimum door thickness of 1-1/4", much sturdier than the standard 3/4" baggage doors.