Hi,
Most good / high-end AV shops will have projectors on display to demo.
Not sure if you have any experience with projectors, but incase you don't, here is some info:
* Generally, projectors can only be used in a room where you can control the light in the room - i.e. it needs to be pretty dark, otherwise the picture is very washed out. That is why most people only use them in dedicated cinema rooms or only use them at night, or have very thick curtains on all windows.
* I don't think that a projector will be great for general TV viewing (esp. in the day, for the reasons above).
* Projectors are normally used when the viewing distance is quite far - where a 50" LCD/Plasma is too small. So, if you are say 4m+ away from the screen.
* If the picture you project is very big, normal TV (standard definition) won't look very good. You'll have to sit quite for away to not notice the artifacts/low resolution.
* HD (esp. Full HD Blu-ray) will probably look very good projected quite big

but Full HD projectors are expensive.
Cheers
Greg