I have been using a Fit-S with the larger (27 x 11) kb shelf for the last 3 years and generally like it. The one thing that it needs though is a longer keyboard shelf. I use it for my CAD workstation and have a standard keyboard, wheel mouse and a 3dconnexion Space Navigator shoehorned onto the keyboard shelf. My mouse pad (5x7 WOW!Pad) is 5" wide so it just fits next to the keyboard and end of the shelf, it would be better if I had more room for it. That leaves about 4" for the Space Navigator.
I may be changing over to a SpaceMouse Enterprise which has a larger footprint (approx 9.8 long x 6.1 wide). In order to fit all these tools onto the kb shelf it needs to be at minimum 30 inches long and ideally 33-36 inches long. It would be real nice if you could come up with something in that size. I understand if you have to wait for a product manager to implement this kind of change but it would be nice if something could be done soon. There may be a market niche here for the longer kb shelf.