However since my house is in Richardson (in one of the more coveted neighborhoods) running an average of 21-26 DOM, I just can't justify letting go of 8-9k in commissions to a listing agent. 

Hello BP,I'm working on converting a family room in a SFH into an attached accessory unit and could use some referrals for GCs that are decent quality and investor-friendly in the Bay Area.

I got a permit for it (an Accessory Dwelling Unit, required in Bellevue, WA) and I live in that unit (when I am in town). 

Alternative options: Properties with garage apartments, accessory dwelling units, or possibly master suites that you could enter from an external door and just hole up without ever having to see the people you're renting rooms to.

Santa Cruz county is in the process of modifying the permits and fees on ADU's (accessory dwelling units) I'd wait a bit to see how this all shakes out unless your in a rush.

I'd love to find a property with a garage apartment, accessory dwelling unit, or a duplex to live in while also being able to have a renter pay for most of my mortgage.

Most are not worth tearing down, especially the coveted bungalow style. 

Do you know about Garage or accessory units etc

Some locations allow for an accessory dwelling to have a legal apartment above the garage, some don't. 

In these areas, you can rent the accessory unit ONLY while you reside in the primary structure.