Well, I had to deal with that enhancing the WebUI MASS (I know is not the same, but IMHO is valid example)
Enhance mass change process for Sales Orders in Web UI - Enhance Item Query
I also found this notes (which I didn't have enough time to analyse) about this topic:
1318262 - RFW FAQ - Reporting framework.pdf
1527039 - Enhancements in CRM Reporting Framework
So from my point of view, If AET doesn't enhance the search, I would try the CRMC_REPDY if this also doesn't fit I would go for a specific BADI, but this will be on theory, performance is something mandatory here as we are dealing with the super heavy OneOrder model, so the best approach will be a balance between performance and maintenance and this depends purely on your business process, which is different (or not) for every client.
Cheers!
Luis