Itamar, Dallmeier does have a few real demos here, but they only show the 4 imager model.
One reason that Dallmeier is vague is that performance / coverage depends on the number of imagers and focal lengths choosen.
According to Dallmeier's promotional booklet, which has the most details I have seen, "models with 4, 7, 8, 14, 15 and 17 modules are available." And those models can be oriented in different ways - landscape, portrait, etc.
These are a few examples of sizes / form factors:
Also, the lens selection impacts coverage area / pixel density, etc.
Here is an image that displays 3 different focal lengths used in a 4 image model:
Notice that there is 1 wide / full imager, one in the 'middle' of the image' (#4) with a longer lens, and two up 'top' at the far field of view (#2 and #3) that have the longest lenses.
To your specific questions:
"What is the area size that a 51MP Panomera unit can cover and get a good facial recognition."
Answer: Depends on what model you choose, what area and what focal lens lengths. I am pretty sure you will have to talk to Dallmeier to get clarity on this.
"Also what is the FPS of the 51MP when compared to the 2 FPS of the 29MP and 10 FPS of the 16MP?"
Answer: Dallmeier says up to 30fps for all imagers, because they are using multiple lower / regular 3MP imagers instead of one 'giant' imager.
"Last is the 50,000$ "street price" of the panomera unit is real or exagurated?"
Answer: Depends on the configuration choosen, number of modules, etc. but I would expect it to be in the tens of thousands USD, given the number of imagers involved, the custom built, Dallmeier's typical high pricing, etc.
Btw, both options are proprietary so enjoy the lock in :)