I don't use accounts much, but UTF-8 would be cool indeed.   (utf-8 is actually always cool)

Character set issues give me headaches.

So I just ran a test at the command-line, moving 500 testnet bitcoins to an account named "฿"

The account created is named "\u00E0\u00B8\u00BF", which is not what I intended.  E0 B8 BF is the utf-8 representation of the unicode Thai Baht character.

Thinking this through, trying hard not to get a headache...

My terminal window has:  LC_CTYPE=en_US.UTF-8
So when I copy&paste the Thai baht symbol, it is being encoded as UTF-8.

I pass a UTF-8 string to bitcoind, and it uses the JSON-Spirit library to convert it into a JSON string (which is defined to be Unicode... encoded using backslashes, I think: see http://www.ietf.org/rfc/rfc4627.txt ).  And there's the bug.  Maybe.  I think?

Command-line bitcoind should be looking at the locale and converting JSON strings to/from that locale.  Anybody motivated enough about internationalized account names (and send comments) to teach it to do that?

RE: point you in the right direction:

File rpc.cpp, the CommandLineRPC method:

I suspect what needs to be done is to properly JSON encode any strings passed via the command line.

And then properly decode/recode any strings returned from the JSON RCP call before printing out the result.