Ill sell you a perfect L20 to build plus some cash for your KA stuff... Im just up the road from you :) Hell, the L20 is in Tacoma haha.
As mentioned youll be a pioneer as Ive not heard of many KA-A10s. Youll have to head out into unknown territory to get the swap done. Im sure its nothing crazy, but there still will be some speed bumps youll have to work out on your own.
L-Series are a great engine and I think any well built L20 will be a blast to drive. Throw in a decent cam, an upgraded carb, and an EI dizzy mated up to a 5-spd and you should be a fucking star.