I can confirm that the chainring offset is different between the two bikes as they should be as the Nexus hub has a smaller chainline offset than the Rohloff hub. The crank length appears to be the same (measured by tape and not calipers) but the Rohloff Birdy doesn't have the spacers on the left side of the bottom bracket. I assume they are on the right side but it's difficult to see as that bike has the extra chain tensioner that's clamped to the bottom bracket.

I'm planning, when the weather is amenable for bike fiddling, to try fitting the derailleur clamp and derailleur onto the Rohloff birdy to find out, as a matter of curiosity, if it will fit OK with the bottom bracket and cranks shifted to the right.

I'm well aware that the Nexus and Rohloff hub gears are somewhat different, both in performance and price. The new Birdy is my third bike with Rohloff gears (but I must rehome one of the others as it hasn't been used for nearly a year). The Nexus hub has the disadvantage (apart from the smaller gearing range) of the twist shifter turning in the opposite direction to the Rohloff shift so, when I tried the Nexus Birdy, I kept shifting gears in the opposite direction to what I wanted.

The Rohloff Birdy has been both up and down the worst hill on my local cycling circuits. We got up the hill with a couple of gears to spare but 40mph (>60kmph) going down was, I felt, plenty fast enough as the steering was feeling a little twitchy and lacks the inherent gyroscopic stability of a full-sized wheel. I didn't try going up that hill with the Nexus Birdy as I knew that I would run out of gears.