I have very oily fingers, and even the most durable keyboard only seems to last 6 months for me. I'm currently using an Enermax KB007U-S Silver keyboard which seems to be holding up okay, but it's been 6 months and the silver paint on some of the keys is starting to disappear. The space bar has already lost a lot of paint. I would appreciate a keyboard similar to the Enermax: 104 keys (I don't need any special media keys aside from the basic Windows key), wired (I don't care for or need wireless in my setup), and solidly built so it doesn't shift around when I'm trying to type. Money is not an issue; heck, if the letters on the keys were made of a different material from the keys I would happily go for that. It seems that any keyboard that uses any kind of painted/printed keys at all is not safe from my fingers. I do wash my hands early and often, but they are just naturally super oily.
Have you ever considered full metal keyboards? We carry a few different keyboards here at DSI that would be perfect for you. The keys aren't painted on, but etched into the stainless steel keys for durability.
I actually did stumble upon your site in my search, but unfortunately you don't have a keyboard that has a more standard layout (I'm not fond of trackball mice). I ended up going with a Deck Legend since the keys are imprinted subdermally (sp?).