They have short throw and ultra short throw projectors. Your screen size is going to be a factor if you can't properly control the light in the room. It's going to be a HUGE factor!

You can search for short throw projectors here:
http://www.projectorcentral.com/projectors.cfm?g=1&hide=0&st=1&mfg=&p=100&p=6000&w=&r=&br=&ll=&t=&db=&dt=&c=&ar=Wide+%2816%3A9-10%29&dvi=&sp=14&pjl=&pjw=&pjh=&td=&i=d&is=&sort=brt&sz=15

Something like this:
http://www.projectorcentral.com/Optoma-TW675UST-3D.htm

Sounds good, but if you look at the image size, it can only do a screen diagonal of up to 103". This is well under the size you are looking for.

Something like this:
http://www.projectorcentral.com/Optoma-TW610ST.htm

Can do up to a 200+" diagonal and still remain in focus (not very bright though at that size!)

173" width is 108" tall with that projector (have to work with real aspect ratios), so you will have to crop the media approriately.

The projector will be 7 feet 6" from the screen at that size.

It claims 24 lumens per square foot, which is about 1/3 of what is recommended for a normally lit room. So, the room MUST be dim for best results.

Projection calculator here:
http://www.projectorcentral.com/Optoma-TW610ST-projection-calculator-pro.htm

Quote (Pixelwix on Aug 13, 2012 11:57 AM): also you need to control the image size from overshoot and position problems try Pixelwarp keystone. Regards chris

Thank you so much for your help and advices! Hopefully it will work out.
Best
Masha