Craigslist (I only looked in the San Francisco Bay area):

http://sfbay.craigslist.org/eby/hsh/4143291349.html

I second Craigslist. We had one shipped from the east coast to the Midwest from a private party who had a new, never installed sink.

A caution though if you go this route. Kohler won't honor the warranty if you don't buy from a real dealer.

Try Amazon. I got a discontinued Kohler Torq aucet for 60% off as open merchandise.

If the Kohler website lists regional distributors, you can try calling them directly. They may have one in the "back room".

eBay, and adhuntr to search all cities for craigslist (albeit a few days behind real time). And any regular vendor that may have one in the pipeline.

i have had success with this blog,
http://discontinuedkohler.blogspot.com/.

try this faucet guru guy.

Here is a link that might be useful: discontinuedkohler.blogspot.com/

Very late in noticing this post. However, the undermount version of Marsala is Executive Chef. I will be buying one of these soon and selling my self-rimming Marsala.