For a 14 ft. viewing distance you should consider at 120" to 135" screen (diagonal). Rule of thumb for 1080p resolution is 1.5X the screen width, but some people like to sit as close as perhaps 1.2X screen width (especially for watching 3D). For example a 120" diagonal 16x9 screen is approx. 105" wide therefore 1.5X this value would be approx. 158", or just over 13 ft.
You should post your question in the Display Devices >> Digital Projectors forum here at AVS. There is a separate section for projectors under $3K and another section for projectors over $3K, There is lots of threads on 3D projectors including comparisons and various post about screens for use with these projectors. You may also want to check out projectorreviews.com.
Ron Jones Blog + Reviews + Articles: projectorreviews.com