I'd like to have a PJ that I have the option of mounting on the ceiling OR the floor.
From what I gather, keystoning is the primary issue.
My first quasi-question is, does keystoning occur if the PJ isn't exactly in the middle of the projected screen? (height wise)...b/c it seems most of the designs I've seen are pretty low to the ground...

Secondly, if that's the case, in order to have the flexibility of mounting either way, it's necessary to compensate for the angles - split design. (Is there anything else I have to keep in mind?)
Is the only other thing being able to mirror the image, either by software or flipping the lcd upside down...
Oh, and ventilation I suppose is also an issue...(exhaust/intake to the sides)

Is there any difference in the design of the enclosure for split/unsplit designs...or is it possible to use both methods in any enclosure? (ei is it just the sled that's different?) *I'm interested in purchasing a HAAS from tescorp, if that helps

Thanks!
Feel free to add anything else that may be relevant <---noob here

1) Yes, keystone correction is required when your pj isn't exactly at the middle of the screen. those designs that are low to the ground likely use keystone correction.

2) the split-design is the only option for optical keystoning (ie. without modifying the source image).

3) yes, make sure your lcd panel is kept below a its maximum working temperature

4) it should be possible to use both methods in any enclosure. however, some unsplit design enclosures may not have enough room for the positioning of both fresnels, let alone keystoning (none in particular, just giving a warning). also, the focal lengths of your fresnel and triplet will determine how much space between them that you need.

Small correction there. Lens shift also corrects keystone and can be done (though to a limited degree) with either split or unsplit optics.

I see, excellent, Thanks!

Oh, yeah, I forgot about that. Partly due to not fully understanding it.. a lot of people are talking about it, but I can't find any explanation as to how it's done and perhaps some examples. Could you provide me with some links or maybe the explanation?

edit: oh, I know how it's done with split optics, what I'm unsure about is for unsplit optics.

edit edit: doh, it's all in the guide. for some reason I forgot about the unsplit one.