I understand what you're saying -- but, personally, I'd look for other ways to solve the problem.
What platform are you using? AIX, Solaris? Many platforms let you turn-on a "Large Files" option. If you do the same in Progress then you "can't" fill-up the database. The worst that'll happen is the last DB extent (variable) will keep getting bigger. But, so what?
Like I said, I'm not keen on the idea of having a second DB. I have a feeling that you'll just create more work/problems for yourself.
However, if you decide to go ahead and create another DB, let me know if you need any help with it.
Ron.