I just did a quick search and came up with nothing as well. Typically when I run into this situation I will reference the manual and get a part number. for instance instead of searching for parts by game I'll drop the part number in the seacrh engine instead. I'm amazed how many times I find a common part but was unable to locate it by machine title.
My two favorite places to shop are pinballlife.com and marcospecialties.com
Go through mrpinball.com parts search.
When all else fails post a WTB over at RGP.
You can try pin resource he might have something if you have the part number. Other than that I would guess ebay or maybe calling marco and talking with him about it.
What a weird coincidence... I was just looking at your site earlier today. I found it through a google search. I'm considering a Star Wars with an R2D2 problem.