In reply to Anni:
The tops off supermarket squash bottles also fit platypus bottles, which is useful when you don't want them in "hose" mode. If using the hose attachment in winter, blowing the water out of the tube after drinking from it will stop it freezing up.
The old-style Petzl Meteor doesn't have a headlamp attachment, but a fairly effective one can be bodged on by tying loops of elastic through the front and rear ventilation holes.
Extra harness gear loops can be attached using cord and plastic tube (pics on my gallery).
When camping, you can squeeze the dregs out of a gas can by standing it in a container of hot water from the campsite bog block.