You should be able to buy a Rule 360gph 12v bilge pump for about $25-30 at any boat store. They're about 4"-5" high and about 2"-3" in diameter.
They are a lot smaller than freddy flintstone foot pumps. :-)
The battery is a bit heavier, but we are working on that. Put that behind the bulkhead.

: I'd skip them and buy something that has a track record in kayaks or canoes.
: I'm sure that JohnK can let you know what he uses; it sounds like a good
: model. Not sure how much it weighs. I saw a decently light pump outfitted
: into an Esquif ww canoe. I believe it was Rapid Runner and ran around
: $250US. You may be able to make your own for around $150US if you own the
: tools to do so.

: I've always thought a small self-contained pump connected to a small foot
: pump system would be cool, but I abandoned the idea once I took into
: account the weight of everything.

: Do you end up paddling alone often?