I'd like to make a HDTV (1920 x 1080 = 1080i and aspect ratio 16:9) projector.
Is it possible to use 17" (4:3) lcd screen or should I use 15,4" widescreen lcd?
And how I connect to the projector with dvd-player?
(Sorry about my bad English. )

The only way to achieve true 1920x1080 native resolution is to use a high res LCD panel such as a Sharp. There's a pinned thread in the
Trading Post with info for than panel. You can also use the search function to find plogs and other information - search for the words
"Sharp" or "WUXGA".

It depends what inputs your LCD has. If it only has VGA then there are some dvd players that have VGA output (according to others in the forum - I haven't seen any myself). You could also connect your computer and use the dvd drive in it. I believe there are also some converter boxes out there that can convert the signals from the dvd player to VGA - hopefully others can suggest some for you. I have my computer connected to the projector so I wouldn't know which converter box or dvd player to recommend to you. Hope that helps.

A lot of people use Nextvision TV/Video processors from Viewsonic, such as the Nextvision N4. This will allow you to play video on your monitor with only VGA RGB input from sources with coaxial (cable, satellite), s-video (dvd players, cable boxes), and RCA (game consoles, dvd players) outputs. Some monitors, and I imagine every LCD TV has RCA inputs so this would make dvd-player hookup easy as pie.

The Nextvision N4 sounds good but it supports only 1024x768 @ 60Hz resolution. I'd like to connect only a dvd player to the projector. The best solution would have HDMI connector...

1024x768 is well above the resolution of a DVD. The N6 supports 720p (and up to 1280x1024). You could use an RCA to RGB (VGA) adapter for dvd to monitor.

If I use for example a controller board like this http://members.cox.net/minoten/specs.shtml
and I connect my dvd player to its dvi-d input or vga input. Can I do it without any computer or graphics card? So with this controller board I need only a (hdtv) dvd player that can produce 1080i resolution?

By the way thanks a lot for helpful answers. This is great forum.