The rear port avoid the rear wall is a fallacy.
The port is a pressure relief system that allows part of the bass wave to evacuate from the cabinet, allowing for greater efficiency which are the Thiele and Small parameters for building a ported loudspeaker.
The total bass output of a loudspeakers takes into consideration all of the acoutcial output of a loudspeaker, placing any loudspeaker closer to a rear wall will increase the way the loudspeaker couples with the room and increase bass output which will directly affect the speakers perceived tonal balance.
A loudspeaker's bass output whether it is a front or rear ported loudspeaker makes overall very little real difference, the combined output of the loudspeaker, the placement in the room and the room's overall acoustics are what matter.
Also a port can be partially blocked which will change the speakers loading.
So I would look at any speaker which accomplishes what you want, you will need to work with any high end loudspeaker no matter what in order to get the loudspeakers to perform.
This will include Shatki, Acoustic System Resonators or similar devices and possibly tube traps.