Axeli, Welcome to the forum.
Interesting thoughts. I've given it some thought myself since I have a few broken compounds lying around the house.
All in all, sounds like a job for a set of custom limbs. Wonder if Elkridge would do something like this. Give them a ring, see what they say >>> http://www.kids-bows.com/contact-us.html (don't let the site's name fool you, these guys make laminated hunting prods)
Unless of course you're down to play the game and roll your own...always that option.
As for the trigger...Todd covered it pretty well.
On that Horton, is it an aluminum housing trigger, or one of those sheet metal boxes. A picture would be nice.
If you do go through with it, it will certainly be an interesting project. Keep us posted.