Just a few notes...
DIKU was not built on a levelless nor classless system. It's rather unlikely to find any DIKU-derived codebase to be levelless or classless because, as Samson said, most of the game mechanics depend on both level and class.
This would fit into the department of "making a game your own".
As for accounts, if you do some searching you should find some snippets or even a codebase that has this implemented. Either way, accounts aren't entirely hard to code in. I'm not too sure they fit into how Alsherok is setup though.
One thing to consider with accounts: When revamping trust based on account, I wouldn't allow all characters on one account the same trust. An immortal flag is great, nice to give some basic commands, but not top-level trust. And per-character passwords are also a great idea. The idea is so that an immortal's account with 5 characters doesn't have a central point to compromise should someone feel a tad malicious.