my partner and I successfully conducted a shoot for about 150 odd pax at an aircraft dispersal area before. It was printed into a banner and i could even see the last guy at the back!
used a canon 5d2 and 16-35mkII. I read somewhere that you'll need an equivalent of 35mm on a FF sensor to get the least distortion or something like that. f14 and shutter minimum @ 1/100s to minimize motion blur. ISO set according to ambient lighting. u can try f16 or higher but i again read somewhere that @ f16 and above diffraction occurs. remember to keep your settings constant through all shots, if not stitching will give uneven light tones.
I think i shot in portrait orientation and stitched in photoshop. the result was good!
so there, i guess a pano is good, but always take a "overview" shot in case stitching duzen work for you. it gives an "fisheye" look though, but the people are still proportionate lah.
otherwise, medium format might be your other option. not to sure abt this so i cannot comment much on it.
hope it helps.