For a wall guard I used a kit for putting a rubber seal at the bottom of a garage door. The kit came with an alluminum piece which gets screwed to the wall, and a rubber piece which slides into the slots in the alluminum. It looks very professional and you'd never guess what it actually is. The rubber strip forms a dome or a U once it's slid into the slots. So when a door hits it, it bends inward and provides just the right resistance. There's no chance of damaging paint even if you hit it with the door pretty hard. Since it's very long it covers both doors and would work well for a variety of vehicles.
