Wow, been reading some parts of this thread and this seems like a lovely contribution.

I'm just wondering if the ones who chose to checkout without an account still gets an option to subscribe to my stores newsletter? Because this is really important to me, and to other shop owners, I believe.

linnx - If this module is supporting newsletter signup I'm definately gonna try it out. I'm also using (and I'm very dependent of) the "attributes with stock" contrib, so I will let you know my results once I've tried.