I shoot Pano's with a 1DsIII, so same resolution as your 5DII.
So far, I've found this to be a great sweet spot of resolution, convinience and quality for Landscape Pano's.
Example. Portrait Mode, 90mm TS-E Lens, Single row, 7 Shots, 10 deg Rotation. Will give a 3:1 Panorama (after end cropping) of 16848 x 5616. FoV 75deg x 23deg. (Horiztonal similar to a 16mm lens) ~90MP
This will print 20x60 at 280dpi, and 24x72 at 234dpi, and printed on an Epson 7800, the results are excellent. After much research and testing, and talking to Epson, I will print large pano's down to about 180dpi and be pretty happy with the result. This dosn't quite stretch to 96" without uprezzing, as I find 146dpi a bit too low for close inspection. (I Resize without resampling the print. The printer does a better job than Photoshop at creating blend between the pixels).
Note: As I use a small Manfrotton 300N Indexing pano base, I fix my rotation amounts to numbers which fit that device and provide at least 30% overlap. I've found improved the consistency of my pano shooting considerably.
For multi Row shots, I tend to use the Shift of the TS-E lens, rather than tilt the camera. This keeps the film Plane (Sensor plane) vertical at all times, to avoid falling or converging verticals or other nasy effects. Whilst the pano programs can correct distortion, they toss some effective resolution/image quality to do it, so i'd prefer not to.
I find this is easily enough to give a good high rez shot.
Example: 90mm TS-E, using +/-10mm Shift (near to max), 2 Row's, Portrait, 10 Shots per row. Result 8736 x 26,208, ~218MP.
so that 96" print is now at 273dpi.
I use the 90mm TS-E as an example, as this is my prime landscape lens, however you don't need to use a Tilt/Shift. Although, as a bonus, the other benefits of the TS-E are.
1. Can shift the composition up/down, whilst keeping the FilmPlane vertical. (say, from up a hill looking down).
2. Can use Tilt for depth of field. Although I find this only works well in a single row shot, I have not as yet had any success with multi row pano's with tilt.
I've been working on a detailed spreadsheet of Len's, #shots, rotation, FoV, etc etc for shooting Pano's (along with other things I want to remember when shooting). If anyone is interested I'd be happy to post it when I'm done for private use or comment.
PS: All that said, Stitching is a pain and dosn't suit some subjects (Water, movement, Aerial, rapidly changing light). I'm seriously looking at augmenting the digital with a Fotoman 6x17. Still researching what real resultion and quality equivelents that will give me.