screwfix used to do a lovely pair of 16" slip joint/waterpump pliers, all for 15.99. brilliant bit of kit, nice long thin responsive handles, and they would open wide enough to get a customers neck into.
Stanley were doing an adjustable spanner with a mole grip locking device attached to it. I got 2 pairs a few years ago and they are still going strong.
Ideal for stopping a pipe dropping below the floorboards when changing TRV's for example.
Another plus is that they never slip off when you use them correctly thus saving damage to your hands.