The above link is a search engine that lets you look by zip code, city etc. for political contributors. It is run by the government, so no idea how long it will function these days. It is not just national elections, it does local stuff too (maybe measure 36? Jim Francessoni?)
This link (above) is the indy archive of LOTS of local big republican donors. This list is several months out of date, I think it dates to the Bush visit in North Portland. It only shows BIG donors (over $2000 in one year) and only Oregon donors (so no Vancouver folks). Still good info to have, and you can use the first link to update this.
Last time this list was up, a few people posted that they had found names of people they did business with. People here like to hide if they are republican donors, so that progressive-looking person you buy your cofee from may not be as nice as you think.