I've been trying to follow the contribution status updates and found this link very helpful: http://wiki.civicrm.org/confluence/display/CRM/CiviAccounts+Data+Flow#CiviAccountsDataFlow-Otherchangestocontributionstatus
I have a follow up question/thought. The 'overdue' status is no longer an option for contributions. We had been using this in the case that a donor who had previously indicated they would mail in a check, or the like, never did. We give is a 90 day grace period but then change the status to overdue. (Although we like the language 'expired' better when talking to donors.) We like that this is a separate status than 'cancelled'. In our workflow they represent two different concepts. This is especially helpful when it comes to talking to the owners of PCPs - we can easily see if we cancelled a donation (something we removed due to an error or request) vs a pending donation that simply never came in.
How hard (or crazy) would it be for me to add a custom contribution status?