The RPM range stated with a manifold design is more about marketing than anything else. The average person isn't going to be able to select an intake manifold based on port cross section information etc, so this recommended RPM range is used instead.
A larger dual plane intake might fit the requirements you've discussed for a carburetted engine, but I doubt the ROI is there. Unless Trickflow decide the dual plane market is something they want to pursue.

As far as an intake for EFI, something like the manifold used on the Gen III Hemi, where the plenum sits under the long runners, might be the best compromise. Most of those wanting low RPM torque are probably not wanting to modify their factory hoods, so low profile would be something they'd want.