I wouldn't think this was a particularly difficult thing to 'add' in to MYOB general ledger detail reports (or in the GST/Tax area etc) but we definitely DO need to be able to simply customise our MY...
I too think this is a very good idea.
I use this feature in QuickBooks all the time to check that the right GST code has been used.
Also a very good feature to have when you are doing a report for each General Ledger Account Code to find out what the total GST inclusive costs are per Account. IE contractors, materials etc.