First off your correct about the ratio, stick with it because the 400q was built with lcd panels of the same dimension. If you are going to watch 4x3 material then you will have two black bars on either side of the screen, some people refer to this as a "halo" because light can not be blocked.
Sony makes a nifty utility called PJCalc that will calculate the distance to screeen and size of screen. Using your measurements, your screen size will be limited by the 7 foot throw distance to 58" diag 16x9 screen. If you were to get the projector back to 12 feet you could get almost a 100" 16x9 image.
Here are some suggestions, never sit behind a 400! Heat is dissapated to the rear and it comes out in mass... Try to mount it as far behind and above main seating position as possible because of fan noise and heat. It is a great projector if you can control the lighting and feed it a good source.
Hopefully you will have an excellent time with this little box, I know it has served me well!
Here are some links that may help.
400Q FAQ - PJCALC can be found here. http://www.thebigpicturedvd.com/w400q_faq.shtml
400Q message forum - search on subject before posting. http://www.thebigpicturedvd.com/cgi-...conf=DCConfID1
here is my 400Q and DIY homemade screen. Since you will be projecting a rather small image, the light output will be much higher. You might want to try a DIY screen first. http://www.geocities.com/sstieferman
Hope this helps.
[This message has been edited by sstieferman (edited 02-09-2001).]