i set up a pump, though it is probably not necessary. and i haven't finalized it. i basically put a immersion chiller in a 2 gallon bucket and then put pipe fittings to connect a submersible pump to run ice water through. i use foam ice packs and put them in my mash tun after the grain is out. gravity drain back to the tun.
incidentally, went out last night and the place had a drink - bloody mary with a gravity fed beer into it with a few strips of bacon in the bloody mary part. thought of you