few CRT monitors on the market can display all amiga modes
I remember Microvitec 1438,1538 and 1738
also Nec Multysinc 3D
Microtivec still produces some monitors that works fine on the amiga
however I don't know if the condition is refurbished or new
maybe you can order one
check
http://www.microvitec.co.uk/