I did a really quick search in RMLS: of 4863 active and bumpable listings listed in “Portland,” 183 are Limited Representation (3.7%). I’m trying to think of a situation when limited representation wouldn’t equal FSBO but nothing comes to mind. Once they have paid a Realtor to enter their information into RMLS they are under contract so another agent cannot suggest to the seller that they should list with them if they agent knows that the listing is in RMLS (the seller can initiate that conversation, the agent cannot). This is the typical info in the private remarks:

Take offers directly to seller: Mr. X @ 555-555-5555. Call seller with any questions i.e. Availability Etc. Use a “Seller’s Fee Agreement”. Seller Represents Seller.Buyer to varify (sic) square footage. Contact Seller for appointment to show.

There are 18 listings in Portland on FSBO.com and 77 listing on Craigslist that have “FSBO” in them.

***added 10 minutes after original post:

Thought this was interesting from: Real Estate 101 – Listing Agent vs FSBO

The number of property owners selling their land independent of a realtor has seen a sharp decrease in recent years. In fact, it has dropped six percentage points over the last decade, according to the latest numbers from Chicago-based National Association of Realtors. As of the beginning of 2007, a mere 12 percent of all real estate transactions were for sale by owner, or FSBO.