Hmmm....Is Maemo Leste working with N9/N950 and N900 including WiFi, phone calls/sms, bluetooth, etc?
Is it in better shape than PostMarketOS?

I don't say your idea is bad, but after viewing their pages I got impression that both OSes are lacking in hardware support and basic functionality. But maybe this info is outdated and I am wrong?

I'm simply curious and fully agree about Neo900.

But why PostMarketOS is ommited?
KDE Plasma is very good DE, so I guess Plasma Mobile is good candidate too.
It's using Qt5, so its direct successor to Qt4 used in Meego/Harmattan.
Its fully FLOSS (unlike SailfishOS, which is more closes than MeegoHarmattan, so I personally think it's unfair it's totally ommited on main page)