thought I'd mention that with ipe , if you do get hold of it, then the main problem is knots, even the small, hardly visible pin knots will often cause compression fractures on the belly....so dont but ipe with knots...the grain is obviously better straight if you can get it, , but I have used run off grains on bellies with no problems at all, many times...and I believe it is absolutely the best match for bamboo, its a lot harder than osage, so therefore it will perform different to osage, one will be better than the other, IMHO ipe matches boo best....of course then there is boo and there is boo!!
Dave