How can Brommies get more gears. Alfine/Nexus style hub gears are quite heavy. Brommies need a rear chain slack device for folding anyway, so adding some cogs is easy. 3+2 is a reasonably sensible way to go. Is there space for an 8 or 9 speed cassette in the 115mm frame dropouts? There would be much more risk of oil contamination of clothing from all the exposed cogs.
Kinetics make Rohloff rear ends and disk forks for Brommies, if that gets your goat. An "ecosystem" of 3rd-party support and bits is always useful.