So I took all the good advice on here, and other places, and came up with an interesting design. Let me know what you guys think.
The general idea is 2.4 cf box, externally braced, with an 8.5"x11" swappable port, with 2" of sealing surface around it.
Tunings are 70, 53, 43 Hz... 3 of my possible Street Beat song choices, and a daily setup tuned to C4 alignment (23 Hz). If all else fails, it can go seaeld.