First of all, I'm buying a NES/Famicom Everdrive day 1. That would be awesome. I've got a Super Everdrive, Everdrive MD, and Turbo Everdrive already and would love to have as high a quality NES solution.
All this said, Krikzz you really should reconsider the Neo Geo AES Everdrive idea. The games are _insanely_ expensive. Some of the best cost more than $1000. I've owned a few Neo Geos and love the console, as do many. In the end the cost of the AES games (or an MVS to AES converter + MVS games) is just so high it's extremely difficult to justify the expense. If I could buy an AES everdrive, even for $300 or more I would do it in a heartbeat. To just be able to play all the Metal Slug games on real hardware without spending thousands would be worth it. Add to that all the rare Neo Geo AES games that are worth $1000+ and the purchase is a no brainer. I know it may seem like not that many people would buy it, but the price that people would be willing to pay for it could be a lot higher than you'd think. Even if you didn't sell that many, people would pay a lot.
All your stuff is great, whether you do Neo Geo or not, seriously... it's awesome.