Just got to thinking about this in relation to a speaker building project. One problem with rear-ported speakers is you can't shove them back against a wall, which many listeners have to do because of room limitations. There are certainly speakers with side mounted woofers...the AR9 for example. Why not side-mounted ports? I can't think of a reason this wouldn't work. Theoretically you can put the port anywhere you want, right? So why haven't I seen one like that?