I've tried playing Nuzlocke some. Honestly didn't find it very cool. If you don't restrict pokemon centers it doesn't actually make it harder, it just makes it more grindy. And if you do restrict them it becomes really hard. In a way that I didn't find fun at least.
Tiny bit late on this, but IMO Nuzlocke runs are way more fun on an emulator than on an actual system, if only because the ability to speed the game up to 10x speed makes you able to do the required amount of grinding in a sensible amount of time. Being able to get through a battle every 10 seconds instead of a battle every minute is a
huge difference in the fun levels.
And personally I prefer to do:
1) First pokemon only regardless of duplicates + any shinies encountered
2) No daycare or trades, but the free egg and given/bought pokemon from NPC's are fine
3) White/Black out is game over, even if you have backups in the box
4) Needing an HM pokemon and not having one is a pseudo game over, unless you enjoy grinding until you find and catch a shiny that can learn it
5) Legendaries are allowed, but in most cases by the time you could catch one without throwing away half your team you don't need them anyways
5) Switch style battles because the extra advantage lets you cut your grinding time by a third, even with the emulator speed up I still have some limits.
Sadly my last Emerald Nuzlocke run ended when I ran into Brawly with only pokemon he was super effective against, but this current run I'm already up to the point of needing to Surf around. (And the shiny makuhita and poochyena that I ran into and caught have certainly helped!
)