"financially attractive hardware solution"
To be honest. i have a setup at home and my biggest problem are the eletricity costs to run this stuff 24x7. When i compare to a bunch of VPS at some hoster for a couple of bucks a month...
I don't know what your electricity cost is but keep a eye on energy constumtion of your setup. Whatever concept you want to run, don't use "old cheap Datacenter stuff". You will pay a lot in the long run.
Just my 2 cents.
You know that you can just edit the notes files with any texteditor you like on any system that is, at least, capable of webdav? I edit my notes with my iphone on the default "notes" app, as example.