Hi again,
Don't know about a longer power lead - have a look
here for a cheap replacement - you could "graft" a longer cable to this - use decent quality mains in-line connectors ( the kind of connectors used for connecting the power leads on electric lawn mowers etc.), if you don't want to butcher the one that came with the projector.
The AE100 would have to be about 4"
lower than the top of the screen - to check exactly, set up the projector with no keystone at the distance required on a coffee table/similar (even pointing at a wall will do), measure the distance between the floor and the centre of the lens, and measure the distance between the floor and the bottom edge of the image - you should find that the distance from the floor to the bottom edge of the picture is about 4" (or a little more, can't remember exactly) less than the distance between the PJ and the floor. When you've identified the difference, you should add this amount to the distance between the ceiling and the top of the screen to find the distance between the ceiling and the position of the lens of the PJ. Hope this is clear - dead easy to show, not quite so easy to explain in words !!
BTW, I'm deffo not being ar$ey or anything, but there's a link in the FAQ (sticky at top of page) to a thread about setting up a screen where you might find I've explained this in better detail (just remebered now!! -
here's the link.
All the best,
Sean.