I've seen a lift, but as it cost £1700

I figured that I'd try to make my own. However, everytime I think I've found a solution, it turns out that I've overlooked some detail and it won't work/fit.
I bought some drawer slides; the dearer type that stay in one piece whatever way you tilt them, but realised that they are too long to fit in the void between my ceiling and the floor of the room above( approx 8 inches/200mm).
My idea is to have a swing down loft hatch type door, that is not connected in anyway to the PJ. Then have the PJ mounted on a thick piece of marine ply using parts from a ceiling mount I bought. The idea would be that this marine ply 'ceiling' will be attached to the joists somehow using a slide/scissor arrangement to allow it to be manually lowered once the 'loft' door is swung out of the way. BTW, I need access to the controls on the bottom (when upside down that is) of the PJ for lens adjustment.
I did find some gas struts (like car boot closers/openers) but they were about £60 each and I reckon I'll need 4 (one in each corner). At least they would give a controlled descent to avoid damaging the PJ or it's lamp...just not a cheap solution and they didn't seem to have much travel for the short length required when in the stored postion.
I guess it's my fault for assuming I'd be able to do this simply and cheaply.

My PJ is quite large and a bit too ugly to have permanently fixed to the living room ceiling. I can't leave it on the rear sideboard forever (although it works well enough there). I've manage to build a pelmet to 'stealth' the electric screen (not quite finshed yet, but at least I've sussed how to achieve the result I want.
Any ideas welcome....better yet photos of anyone's succesful DIY creations.