I got my arcadecab out of storage, got 3 months out of it and the monitor died

Been like that for a over a year now. I just want it to work now I have looked for replacements and I not getting what I want. So I decided to go for a 24" LCD. They are cheap and big.
But aspect ratio, my plan is to install it vertically.
The problem is what mame front end will aspect ratio with black bars?
regards,
jippie