I've been a premium member for 6 years. I'd pay double to be "super-premium" (whatever you want to call it), if you'd increase the maximum note size. The benefit of Evernote is to track an entire project form estimating through bidding through selling through shipping through invoicing, etc... Several times per year I hit the low 200MB limit and have to either split my project into multiple notes or start deleting some of the history (which I'll never get back).
I've seen responses to others saying "why do you need to store all those files in the note?" Because that is why I use Evernote! If I wanted to have folders full of project files without context (i.e. notes), I wouldn't need Evernote at all.
P.S. Instead of creating a new membership level with much higher maximum note capacity, maybe just double or triple the capacity for business members.