I was looking around for an X3 hot key reference and I found this: http://www.editorskeys.com/products/audio-editing-keyboards/sonar-x3-shortcut-keyboard/
It's the first dedicated Sonar keyboard I've seen. Pretty cool.

I have had other kinds of pre-labelled keys for other purposes on keyboards, and they always seemed to wear away until unreadable fairly quickly.
 
Would it work instead to create a Word document with your most-used key combinations sorted at the top of a list, and just kept near you?
 
That's what I now do, and it works well for me, and only cost a smidgen of ink and 1 piece of paper.  I used an easy to read font size, so I don't have to do much more than glance over at it to read it.
 
I suppose I could splurge and get it laminated.  :)
 
Just a thought.
 
Bob Bone