Lol. Mithala with dual form? Hahaha xD
I know its possible to give form songs to people with nodes. And I'm sure Edwards could come up with a way to make a timer go between maps. So really, with the Native mod there is no reason why this can't be done relatively easily.
I mean, all you have to do is make each boss map link on to the next one when you win. Although you'd have to edit the boss AI script for that since its the script that fires when the boss dies not a node (note: you'd want to cut out the story sequences the show after some of the bosses I think. They are actually separate maps so you could use that same line to go to the next boss instead of showing the krotites or something

).
And you give the player the new forms they should have on entering each map with some special nodes. It shouldn't really be that hard. The hardest bit would be removing the lead-up to the boss (some of the bosses have quite a bit of map in front of them, like the one in the icy veil). Removing that area could mean drawing a new map template, which we dont have the original copies of so it could be tough. The other (simpler) option is to just remove everything dangerous from the map the boss is in, and fill it with bright, easily travelled water so you can get to the boss as quick as possible.
(Oh, and thanks for the mention Zeke

(I made that Energy form battle) )