You might look into the Benq 7000 in the range of $1500. With it's lens shift, you can get it placed pretty easily, but you still may need a ND filter on that screen. Pros/cons vs price breakdown here you can look into. http://www.avsforum.com/t/1391476/coderguys-top-projector-picks
Lens shift allows for physical movement of the lens to accommodate the pj to be placed above/below the top of the screen, where a pj with no lens shift, that distance is usually "fixed".
Throw distance is the distance from lens to screen where some pj's are made to work with smaller distances, and normally the further away you can mount the pj, you might get a little better contrast and sharpness.
Native resolution basically is the inherent resolution the panels will display. Most home theater pj's in the $1000 and up range, will be full hd resolution, or 1920x1080 (1080p). There are a few lower cost units in the $700-900 range that are as well, however.
LCD is normally not quite as sharp as a dlp, but usually have more "lens shift", but can be troublesome with not having good convergence. All three panels being perfectly aligned is pretty rare on a 3 lcd pj. If it's within 1/2 pixel difference, that can be considered normal however, and not seen from seating distance. Some less expensive dlp units can be bad for having (RBE), rainbows, when bright lights are in the picture or movie. Their just different display technologies which offer a little different overall image "look".
LED, no bulb to burn out, but most atm are mainly lower level blacks/contrast and less resolution, than bulb pj's.
Hard to say if a pj can be to bright, but ND filters can be used to tone down a pj if it is an issue, with some calc's online offering advice on lumen output needed for certain environments and/or screens. Each affecting how much brightness might be needed, but normally for 3d, brighter is better.
Good luck with finding a pj that will last you a full 10 yrs. 5-6, sure, but 10 may be asking to much.