Something like this?

http://portland.craigslist.org/clk/bik/790059098.html

This one might a bit small and a bit $$$:
http://portland.craigslist.org/clk/bik/787905080.html


Search nearby areas as well, the above one was linked from the Washington CL for Clark County.

This one is probably too small and too far away:
http://kpr.craigslist.org/bik/793569548.html

Or just plan a weekend trip up to the Tri-Cities and buy up all the cheap ones and flip them back in Portland, you might be able to recover the gas money or more.
http://kpr.craigslist.org/bik/772560109.html