Still .. better that these things happen now than in the future, where things will seriously break.

Note: I would suggest a max cap, because no matter what datatype you use, someone could simply issue 999999999999999999999999999.... coins as an attack.

I haven't tested non-alphanumeric characters in the asset name yet -- is there support for that or will I crash something again?

Also check for overflow possibilities in trading, dividend payments, bets, all that.