Line-Item Cost Object PO and/or Invoice approval

[Workflow]

Hello Workflowers

There was a thread on this back in 2000, I thought it might be interesting
to discuss once more the matter of line-item approval within the PO and
Incoming Invoice approval workflows. Perhaps  someone has some new insight
on this matter, maybe there even exist some standard add-on solutions on the
market, or maybe SAP is working on it in Netweaver??? :

Summary for new-comers : SAP standard release scenarios deal with the whole
purchase order or the whole invoice document and not the line item.  The
line item however points to the CO costing element where the budget is
consumed.  It has been my experience that customers almost always would
prefer a line-item approval process as soon as several CO costing objects
are referenced in the same header document.

Has anyone implemented such scenarios lately ?
Was there a lot of development involved ?
Other insights ?

I'm a developer, so I've tended to extend the Business Objects BUS2081,
BUS2012, and FIPP with multi-line virtual attributes linked to a
sub-workflow driven dynamic parallel processing.
This has worked wonderfully from a technical point of view, but you do have
to develop your own Business Object, attributes, and methods after which
some customers do not look highly upon you.  (too complicated, not
transparent, etc., you're making yourself indispensable).