Since I believe* the existing Maemo kernel makes best use of the hardware, it should already be armhf compatible. No idea if that's actually necessary or if an armhf-compatible libc would suffice, but if it is necessary that shouldn't be a problem.

Well I think recompiling the whole Easy Debian software doesn't make much sense. If that's what you want to do I think Arch or Gentoo would be better distributions. Plus, recompiling every binary with armhf support would practically mean to create a new architecture on our own. I have thought about that earlier but I didn't find it practical then and I don't think so now.
That's where the Debian's official armhf port comes in handy now. Theoretically we could start building armhf images right away. The reason why I think there will be a delay of over a year is that it doesn't make much sense to base Easy Debian on Testing or even Unstable since it's supposed to be useable for everybody, not just for Debian experts (heck, I don't even consider myself to be one). Therefore I think the Wheezy freeze is the first date that might make an armhf Easy Debian useful.

*) read: I have absolutely no clue but it would be wise