As mentioned elsewhere, a Sturmey-Archer ASC for forty quid.
It has a hairline crack at one flange, which is why it is cheap (as well as not being advertised as an ASC, just a "3 speed fixed hub"). I know a very specialist welder. If he can't fill the crack, I'll knock out the left ballcup and press it into another shell (any shell made since about 1970 will do).
It has the toggle and indicator, most internal parts are the same as the common FW, and it can be shifted with a 4-speed shifter using positions 1, 2 and 4. Purists grind off the "3" detent.
I'll probably fix it up, test it and sell it for real money.