Mustafa:
If you build it yourself you can do whatever you want... no limitations. The only thing you have to remember is that the focal length of your lens will be the shortest length of the the viewer, measured from the lens to the viewing screen. If you make it so you can change the focus then you will have to device a way to lengthen that distance (a bellows or nested boxes, etc.). As for the movements, some thought on how to do it with hinges, bolts, wood, etc. needs to be given based on the materials at hand. For example, I added swing and tilt to an old view camera some time ago by making a double lensboard with four bolts, one on each corner, and springs on each bolt. To twist the lens arouns all you have to do is tighten the bolts - the springs push out constantly, so the result is a stable platform, although the movements are non-axial (or around an imaginary axis).
Best would be to find an old camera on eBay or other sources. Some of the antique ones, with less-than-perfect bellows will work fine as a viewfinder and could be repaired as you can afford to do it. Most bellows repairs can be done with tape, and most camera repairs can be done if you understand wood work rather easily!
Good luck, don't give up!