Credit card/overdraft credit limit & available funds?

[prl]

Is there some way of entering the credit limit for a credit card or 
overdraft so that GnuCash can display the funds available to draw on the 
account?

I had a look at the documentation and the FAQ, and searched the mailing 
list archive and couldn't find any mention of a facility like this.

Normally we are a long way under our CC limits, but we're currently 
renovating and the cards are getting a good workout to take maximum 
advantage of their interest-free periods, and it would be handy to be 
able to see how far we are from their limits.

I'd have thought that for business users being able to readily see the 
amount that is available to draw from an account with an overdraft 
facility would also be useful.

For now I've just entered the limits in the accounts' respective Notes 
fields, and display the Notes column in the chart of accounts. It's a 
useful reminder, but it doesn't do what I'd like to be able to do.

Have I missed something really obvious here?