Part of the niceness of the UK plug is that if you pull the cable right out of the housing, the internals disconnect in the safest order. The plug comparison sites I've found don't discuss the internals of the plugs much; does anyone know how other plug types approach this (or do they just ignore it)?
Looking at plugs, I suspect that many get round this by making the housing of the plug much more firmly attached to the cable.
They don't ignore it; Schuko (CEE 7/3) plugs also keep earth connected while live and neutral pins are pulled out. Same is true for the French (CEE 7/5) and Danish (107-2-D1) designs.
OP is talking about the failure mode when you pull the cable out of the plug - the live and neutral cables are shorter and tighter and will fail first, leaving the earth wire to fail last.
I didn't quite understand the whole concept. The idea in Schuko plugs is that you cannot pull the cable out of the plug. It's totally fixed (either inside solid plastic, or attached with a strain relief that fixes it).
edit: now that I think of it, Schuko plugs of the install-yourself kind where you can attach cable with a screwdriver (not solid plastic with the cable) are done so that the earth cable is longer than L/N are inside the casing.
Most combination Schuko/French plugs I've seen recently are even designed in such way that when all wires are same length then the PE one has larger slack inside the plug.
Looking at plugs, I suspect that many get round this by making the housing of the plug much more firmly attached to the cable.