Simple decals can be made with a computer printer, either laser or ink
jet.  The secret is purchasing appropriate "waterslide decal paper."
There are a number of on-line dealers which you can easily find with
Google.  I have used papers from Bell Inc. :

http://www.belldecal.com/model_decals.html and Micro-Mark 
http://www.micromark.com/CLEAR-DECAL-PAPER-FOR-INK-JET-PRINTERS-5-SHEETS,7942.html 

The Micro-Mark web site gives a set of instructions at
http://www.micromark.com/html_pages/instructions/decal_instruction.htm 

Since few, if any, printers use gold or white inks, you can not
duplicate every decal at home, but you may be able to create an
acceptable substitute.

By Googleing "player piano decal images" I found images of a number
of fall board decals which might be useful.

Wallace Venable