Wow, I must admit that our games have not yet reached that caliber. The majority of our games are still elimination style.
We have toyed with a few scenario Alternate-Victory games though, but limited to Zone-of-Control or castle siege style games.
Castle siege games we added the alternative objective to kill Realin who usually hides in the top Tower.
Our Zone of control games have been played out two ways.
Glyphs with point values are strategically located at different positions on the map, if youre on that glyph at the end of a round you get its point value added to your score. First team to 20 pts wins.
The alternate was again Glyphs strategically located at different positions on the map, however the first team to control all glyphs simultaneously wins.
Again not a lot of flavor to our games yet, and defiantly no back story (I like how you tied your scenario to the well springs).
We do all agree that we need a bit of a change up from the elimination style games. Recent new waves and expansions have been keeping the elimination game a little fresh.
It would be nice to try out your scenario as a start. I should have enough pieces, might have to scale down the castles a little. I done some casual checking on Heroscapers.com for a good scenario but havent come across anything yet that catches my eye.
However the Quests of HeroScape print and play cards
http://www.heroscapers.com/community/viewtopic.php?t=711 have caught my attention, have you tried these yet?