Ipe is good, heavy stuff. One of the few woods that will actually sink in water. I made a very nice bamboo backed selfbow with it once that shot well till a flaw in the ipe caused it to stress fracture. Sorbothane comes in many different levels of softness. It's been used (and despised) as an audio tweak for years.
I've got some paduak and purpleheart to make a couple of paddle or bench strops with. Just got my leather in today as well.
-in search for the rare element Illudium Phosdex, the shaving cream atom.