Towne Storage is 17 SE 3rd Ave, near the BurnsideBridge (and the skate park underneath, which has a certain attraction for AndrewWoods and DonPark, among certainly others). It's currently full, but officespace.com says the blended price/sqft is $0.40, which sounds good. I can't find a picture of it online. I shall correct that ASAP. 503-236-8298
Here's a map:
