I saw a megasquirt PnP kit. Basically plug and play for any 10/18/14 pin set-up. 22RE, 4AGE, etc.. Has a box of it's own, but I'm sure it would fit nicely in a stock ECU box. Comes as a kit, so probably fit it into any box you'd feel comfortable with. Won't have to cut corners as you would with the microsquirt.
Part #DIYPNP42-K, given # anyway.