Blizniak's Bokkens is a great site. He has dozens of hardwoods at his disposal -- all sustainably harvested -- and can make a variety of weapons. I had him make a laminated jo with the outer layers of ipe and the center layer of bloodwood, and that thing just rocks.
I later picked up an all-ipe bokken on a clearance sale for $80. Weighs more than my hickory bokken, but the thing is really well balanced and packs a wallop.
Dan is a really knowledgeable guy, and will answer your questions promptly.