Apparently (per a PM conversation) this wasn't well known about the Everett area, but Nelson Petroleum sells Sunoco race gas in South Everett.
Nelson Petroleum
They always have 110 in stock and "usually" have Maximal (C16)
Here is a link to the Sunoco leaded race fuel page:
Overview - Traditional Race Fuels
There also used to be 101 unleaded available at the Pacific Pride just south of the corner of Everett Mall Way and 7th Ave S.E. It is a petrocard commercial outfit and isn't manned after normal business hours. I haven't been there in over a year, but I used to buy 101 there all the time for my blown chevy smallblock.
John-