Ok, didn't know you where aware of that. (Sorry Spillage
Here you got the dimensions of the Noritake U-series which is a LCD- replacement line.
The one you are probably looking for is the CU20045SCPB-W5J which is 98.0 x 60.0mm.
I don't have a x3cp, but i think it will be too big.Noritake U-series
Another company is Newhaven. The one most like the x3lcd is the M0420SD-204SDAR1-3, but that one also is way too big.Newhaven VFD line
I can't see this happening if you don't use a 2x20 instead of a 4x20. Then there will be enough space.
Hope this helps a little.