I cannot find a book-closing tool for GnuCash.  This would do the end-of-fiscal-
year closing.  I suppose the entire set of steps would be:

1) create two new GnuCash files, one for last year, one for next year
2) copy all of the last years transactions to GnuCash-Old
3) set the opening balances of GnuCash-New to the GnuCash-Old ending balances
4) copy this years transactions to GnuCash-New
5) create a list of zero-balance accounts in GnuCash-New, and give the user
    an opportunity to delete them

I dread having to do this by hand!