This idea is not totally fleshed out yet, but I wanted to get it up since I think with the right person it could work out well.
The world changes. Orcs and demons move up from the south in the war that never seems to end. The elves provide their support, but seems to worry more about their own lands. The dwarves being master of trades are hidden deep within the mountain passes they defend to the death. This leaves the bulk of the war to be fought by men. The kingdom of Tannerbrook was small and the land rugged, but their king was a good man. He kept his kingdom strong despite the constant raids and small military force. His two sons could not have been more different. Both of them were intelligent and strong, but after that they were very different. Theron, the older and therefore heir to the throne, was a diplomat and man of the people. The kingdom loved him and he loved them. Varion, the younger, was not quite the ideal figure his brother was. Wild and tough he had spent his time with the soldiers and woodsmen. He fought for his country and now he was asked to do something he never would consider.
This could be in a Middle Earth setting or someplace else. Either way this kingdom needs help. Either soldiers to help them protect their borders, money to hire soldiers, or maybe an alliance. Either way I am seeing the soldier son married off for one of these reasons. Could be an elf or human he has to marry. Either way I see the war escalating and these young couple now being forced to not only be together and work out their own differences, but to fight and maybe even quest together.
I would like to flesh out the ideas with the right partner and give this one a try. If interested send me a PM