the Internet Backbone

Everyone (of importance) agrees that in order to claim you're a backbone
you have to (now, not a year ago) be connected to at least 2 public NAPs/MAEs
and have at least one circuit that runs at DS3 or higher speed.

No, that is not correct.
A US Internet "backbone" is one which connects to ALL the NAP/MAEs in
the US. Not just two. All of them.
Everyone else is just a "regional", of one size or another.

Name any ISP which meets that critiera.

[Hint: who is at MAE-Chicago right now?]

Once you start doing BGP peering at T3 speeds in two geographically distinct
regions, you're playing in big leagues. There is a tier below that of BGP
peering at one location; there is the tier above it of peering at *lots*
of places rather than just a few, but IMHO once you have the multiple
peering points you can call yourself a backbone or core provider,
and I'll gladly testify to that in a deposition or in court if you
start going around suing people who use it.

-george william herbert