Are you sure you don't mean a 4:3 monitor? 4:3 is the aspect ratio for CRT televisions and arcade monitors.
I have an old Westinghouse 20.1 1400 x 1050 4:3 LCD monitor...
It's the biggest 4:3 LCD I've seen. Sadly, it's starting to go south. Sometimes, when you turn it on, it only stays lit for a second and then goes black. It takes 4 or 5 tries before it will stay lit.
Even if it was working reliably, I wish the resolution was higher.
GroovyMAME support forum on BYOAC