"I wish I could find a 12-string that sounded like a Guild jumbo and played like a Taylor"
Any guitar can be adjusted to play exactly as you want it to. Taylors are justifiably known to play well out of the box but there's no magic involved, It just requires a good setup. So buy the Guild if you like the sound and modify the action height as needed. I have never owned a guitar, including my two Taylors, that didn't need action work to suit my preference. IMO, all guitars are supplied in "kit" form. You have to adjust them to suit you.