I do too, for dynamics I've got: HD600, PX100, E500 and ATH-W3000. I think I'm done there (unless of course the mythical HD800 comes out of hiding). There are other cans I'd like to own, but frankly the desire to own multiple cans is seriously looking less and less attractive. I'm considering dumping the HD600 as well and making the W3000 my mine large can, but I do really like the HD600 and it's nice to have an open option....we'll see.
I might try to check out custom molds for the E500, but if I did that, I think I'd rather just go with a UE11.