Period total in the chart of accounts?

[Charles Duffy]

Under Preferences/Accounting Period, I have the start and end dates set 
to be relative to the current month. I'd like to have, in addition to 
the overall total column on the chart of accounts, a column which shows 
only the delta for the current month; that way, for instance, I could 
glance at the row for Expenses:Discretionary Spending:Charles and know 
immediately where I stand for the month.

If such a feature doesn't exist, how hard would it be to add? I have no 
familiarity with the GnuCash codebase itself, but once upon a time I was 
quite handy with C (including Gtk), and I've played enough with Scheme 
to know that I enjoy it; guidance on where I'd want to start poking 
around to implement such a feature (and any additional hints relevant to 
the implementation) would be quite welcome.