You could but then again you'd also be spending 3000 bucks per accordion and they wouldnt be nearly as loud as a four stop model. They are ok I guess if you only plan on using them for gigs but you can kinda notice they're not as powerful during jam sessions.
John
The 5 stops are something that was done to add an extra row for what ever reason you want. It can be a dry tuned 4 stop or a wet tuned 5 stop. As far as volume on a 3 stop, I have a C-D that is 12 years old, that is as loud as any 4 stop that it has ever been in company with, and didn't require as much air as some.