I just learned of this site today.
It looks good!
I hope I'm not intruding in this thread but as a Bassist who has built many bass speaker cabinets I suggest you check out Bill Fitzmaurice website.
There a number of good designs for Bass Guitar speaker cabinets for sale.
I myself use a Omni-10 with twin Eminence BP102 drivers.
He has forum that supports builders these designs as well.
Also some myths regarding speaker design and placement are revealed.
Check It out!
http://www.billfitzmaurice.com/ http://billfitzmaurice.com/phpBB2/