What should be synced to an accounting package from civicrm?
Tommy,

I think an extension is a good idea, but a quick glance at the aplos API and it looks like aplos wants each transaction mapped to an aplos contact id.  This seems like a lot of work that is not necessary.  My advice is to see if you can upload a batch at a time through CiviCRM export (maybe a custom search or report) and see how that works first. the effort level will be a lot less.  

I don't know aplos, but many of the small accounting packages assume that they are the transaction system of record and need the contact id passed with each transaction - this appears to the case with aplos.  What you are asking is for a batch transfer with CiviCRM as the sub ledger and using Aplos as the general ledger.  This works fine with larger systems like Dynamics.  I don't see any aplos documentation on JE imports and my guess is that they have not implemented it yet.  

it would be a great extension and many we get aplos to fund it (seems like a biz dev opportunity for Josh of the core team)