In the past, I came up with a short little mission for the foundry and then it got me thinking of making a series. Unfortunate that series hinged on Canon characters and was scrubbed due to EULA.
I was just starting to think about the Foundry and possibly make some war stories (Dominion war, current war, etc) from the perspective of a MACO in a holodeck or a flashback.
My problem is that it would require a lot of ground battles (large ones too) and could me misconstrued as grinding missions. I'd really rather not risk losing my privileges and another policy killing the foundry for me.