Hi Dis,
I don't know of anywhere near you that demos the HT1000, sorry, but there must be somewhere not too far from you I would think. Try posting the question as a new thread and see what comes up.
A 6ft screen is fine for the HT1000. There is no light spill outside of the 4:3 area, but if you watch 16:9 or 2.35:1 movies then the black bars will appear as a very dark grey.
For a 6ft wide screen, the pj can be sited anywhere between 110.6 ins and 133.6 ins.
How far the pj will hang from the ceiling depends on how high you have your screen. Here's a link to the installation pdf:
http://ht1000.necvisualsystems.com/HT1000IG_v25.pdf
At approx 132" from the (7ft) screen, the pj can project from as little as 14" from the ceiling. That can be reduced to 12" if I zoom in to make the image smaller, and move the pj further back - the zoom moves the image up and down a little.
I'm using a 16:9 screen, and you can slide the 16:9 image anywhere up or down within the 4:3 area of the DMD, so it's quite flexible.
I made my own projector mount, so you may be able to adapt the unicol.
HTH
Gary.