I usually game on a 1080p projector with the image about 96" x 170" and I have noticed FXAA is fine, not really too much improvement switching to MSAA considering the fps cost.
However, it is a must to use maximum AF and there is very little frame rate cost.
When dealing with projectors.... specially depending on the projector at high equivilent screen resolutions, the way it's projected actually creates a "FSAA" like appearance naturally.. it's both the benefit and the downfall of using projectors, specially at very large dimensions. Even with a 146" 1080p projector, the effect of fsaa is less noticeable.... it's where hard super high contrasts with per pixel level of detail within a very close range, such as a HDTV or monitor that fsaa is going to be heavily needed...
not saying there isn't any need for it.. just the design of it.
Having run the newer revision of the Panasonic PT-AE7000.... which is considered to be one of the top of the line home theater projectors available today at a cost below that of $4000.... even though it has one hell of a picture.... it doesn't require all that much more FSAA than another screen...