Hello There
I've got a bit of an idea. If you have them, you'll need 4 padlocks.
I will refer to the padlocks by colour, in a effort to try keep things from becoming confusing.
so;
Padlock 1 - Blue.
Padlock 2 - Yellow.
Padlock 3 - Red.
Padlock 4 - Green.
Blue, connects the 2m chain to a solid object like a bed post, or table leg.
Yellow, connects the 2m chain to one of the 4m chains. Making the approximant length of 6m.
Red, connects the 4m chain around your ankle.
& Green then connects the chain going around your ankle, to lock Yellow or the 2m chain. Shortening the length again.
Using the couch roll, make a number of some small parcels. With some pallet wrap over the top to stop them from unravelling, & adding a challenge later on. Put the key for lock Green inside one of the parcels.
Afterwards, scatter the parcels around you. With your wrist/hands bound together, you will have to fiddle with opening the parcels in order to find the key. Where you can then remove lock Green, & increase your movement range.
The key needed for lock Blue, should be placed just out of reach. Making it so you can not cheat & you must unlock Green in order to reach the key for Blue. Once lock Blue is removed, you can then retrieve the keys for locks Yellow & Red from another location.
Notes/ideas;
1) Add weight to the 2m chain, so it becomes like a old time prisoners ball and chain, & makes retrieving the keys for Red & Yellow a little more fun.
2) You can add as many padlocks as you want, Meaning that each padlock unlocked, will slowly increases you movement range & making it as drawn out as you like.
3) The blindfold will or so add another challenge to this.
4) Put some 'fake' keys into the parcels.
Anyways, at the very least I hope this will give you some ideas
gotta go! 
For you of the standing-up-to-wizz bent, consider also that the sound of your own liquid deposit might stimulate you to do it even more. There might be a dehydration hazard here.
