I personally think that it would be an interesting experiment and pretty easy to test out.

I'm not 100% sure but I imagine it could be as simple as:
1. Start up a second copy of darke (much like war)
2. Set all guilds to 100/100/100 devs, or 75/75/75 or whatever.
3. Remove the check from the guild train rooms that checks what guild you are.

The only problem is that some guilds would overlap a lot and some skills (magery!) would become essential to every player.

I don't think I'd want to see that happen to live though. A conversion would be very tricky and a pwipe usually doesn't collect new players.