X4 Replacement Keybed?

[stanV]

Hello

I found an X4 for a good deal at a garage sale a month-ish ago, has no box or anything but otherwise in really, really good condition, sounds great. Only thing is the keybed is a bit used, previous owner must have played it a bit - some keys are much lighter than others, but in general they're all pretty light with a "loose" feel.

Is there somewhere I could grab a replacement keybed? (and one that's more firm perhaps) They're still all very useable so it's more of a luxury thing I suppose.

Thanks