In reply to john arran:
sorry, can't see how this would be practical at all.
I'm suprised no one has suggested the use of concentration, balance, stance and body positioning as a solution.
the climbing partner I probably trust most at the moment is about 9 stone to my 14. She never clips in, and has never let me hit the floor while I've been leading.
I have sometimes dragged her off the floor when I've fallen, but never dragged her anywhere near as far as the first quickdraw, which would stop her anyway.
Don't let loads of slack develop, stand close to the wall, and drop your weight into your harness if the heavier leader falls. If you are pulled in and or up be prepared to brace your feet against the wall. You'll need to experiment with different stances to find what works for you. If there's nothing in place anchor wise at the wall, why not ask a member of staff, and when they say there's nothing, ask them or another climber to whatch you while you experiment until you are confident you can hold your partner?
cheers
Nikki-wow-I-went-a-long-way-that-time-K