I can speak from experience that the Fostex FE207E works exteeeeeemly well in a ported box of about 1 cubic foot. I have the driver mounted on the wide side of the enclosure, similar to Audio Note and Snell speakers. In this case the front baffle is 13"(w)x20"(h). I rear ported mine with a 2" diameter port. I'm still playing with the length for the best in-room sound. The front baffle is 3/4" baltic birch ply. The sides and rear baffle are 3/4" MDF, though I'm going to try 3/4" baltic birch on the rear also.These mate very well with 2A3 and 300B amps. Being somewhat of a cable sceptic, I was surprised how sensitive these were to different speaker cables though.
DaveJ