I suppose the two most important qualities for you is that is has to be removable or concealable and that it has to feel babyish when being used. Not that it has to be an accurate replica, just 'feel' right. I suppose to get that you have to look at what makes it feel like that and find the cheapest way of doing it. The cheapest way will almost always be temporary, so that gives you removable too. You may disagree, but this is what I think would make a good crib, playpen and highchair, and how I would go about making it.
Crib
- Obstructed view when lying in it - it doesnt matter if it is bars or not, just that you can't see clearly because of the sides and they feel reasonably sturdy if you were to lay against them.
- It has to be comfortable, but not too soft. This can probably be made by using babyish bedclothes and not using a very soft mattress
Playpen
- Similar to a crib - the view is obstructed from the point of view of someone in it. Material isn't important as long as it isn't dangerous - just has to be sturdy and block view
- There area within, like a crib, has to be comfortable. This can probably be done by puting a duvet or duvets in it.
Highchair
- You have to higher of the ground than usual. For this the director chair suggestion from Jeremaih sounds good. The most important bit is finding the chair to build it off. After that the other bits should be easy
- Restraints - for a high chair I would think 5 point or 3 point. You might be able to bye some, or if you can some nylon straps, make them yourself. It's just a matter of getting the nylon and the clips and being able to sew it together nto one thing.
- Perhaps most important is the tray, but this is also quite easy. You just need a tray which you can secure to the chair. Good ones for this would be the trays with edges you can use to eat infront of the TV. Then you just need some string or straps to tie it in place. Use a knot that you can easily untie - then it is easy to take the tray away when you don't need it.
As for the material to use on a crib or playpen - not sure. You could use sanded wood, though that might require hinges and stuff to put together, which could be difficult if you aren't good with tools. Though if you wanted all you would need would be a drill and some self taping screws. Removing the sides is a bit clumsy to unscrew, so I would leave an open side, or if you were feeling confident, hinge a side and use some ties or something to keep it shut.
An old thing I've heard. "You can have quick, cheap or well made. Pick any two." I think you want quick and cheap, but if when you've done it it doesn't live up to expectations don't be worried - it will be hard to get something that is quick, cheap and realistic. Then again, you have enough imagination to see yourself as a baby - surely you have enough to ignore some slightly unrealistic props, especially if you are regressed at the time.
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