Would sitting 13' back from a 126" diag 16:9 screen be too close? Due to the location of my equipment rack, I can only have the first row up to 14' away from the screen. I will be using wall mounted dipole surround speakers on the sides and must have them directly in line with the front row.

I do not have the drywall up yet or a projector.

Dan,

It depends on the projector, and ultimately on personal preference. An HD projector will not have as much pixelation as a 480p projector.
You will also need to be concerned with brightness. You can get a higher gain screen and make sure you have a light controlled room. 126" screen is big but there are many projectors out there that can do it.
Viewing angle is another one. If you sit too close to a large screen you can run into that "tennis match" syndrome where you are looking side to side to see the whole screen which can cause fatigue.
There are calculators on projector central that will help you figure out what you can swing.


Judson

These are just guidlines - but you will want to calculate the viewing angle to see if your screen size for your seating position is reasonable. Some people try to dial in the 36 degrees, but if you read the chart, that's the minimum of the "recomended" angle. Note the vertical angles too, as its been said that we are more impacted by the V.A. vertically.

http://i167.photobucket.com/albums/u129/dc_pilgrim/thx.jpg