Hi Ben,
Regarding your item 3:
As I understand it, there are multiple vertical solutions available: ecommerce, Claudio's, dotlrn-ecommerce, invoices, and bill-book to mention a few.
The OpenACS port of sql-ledger is consistent with Claudio's comments (earlier in this thread) about a long term solution.
There are no conflicts, only lots of work to do! =)
The idea is to have the accounts* packages integrate with other OpenACS packages to meet the functional requirements of most businesses, and provide a useful base for vertical solutions and the rest to build upon.
cheers,