I think based on the short fuselage and wingspan, making it close to scale in appearance would make it quite a handful on approach and landing, lightweight foam or not. Just because it is my fave at every museum I have seen it at, doesn't mean I need to build it right now.
There are just too many cool aircraft out there that need to be built in foam! P-61 Black Widow anyone?
I think you'll be surprised how light you can build with foamboard. I don't expect my version of the Peashooter to have any wing loading or slow flight issues.. Short coupled planes aren't generally that big of a deal either, not now that Expo and dual rates are so common.
A friend at my local RC club is working on a foamboard P-61. I've been trying to get him to post it here, but he wants to wait until he has more of it done. It's perfectly doable in foam.