The Medela "Clario" may be a little too small for your needs but take a look.
It's an ingeneous design which has the pump entirely seperate from all patient tubing, collection jar etc, so the pump physically can't be flooded (our main bugbear with suction devices).
It's one of those really neat ideas that when you see it you wonder why no one thought of it before and it seems to work reliably.
Marc
