I saw those and the rizoma (believe me, I looked!) but I am really not digging them all that much. I want more understated and unassuming. I just got DEcosse's MC and reservior since my plunger on the MC is missing the boot.. his is all clean. I'll keep that for a bit until I find something I like. Sadly, I have only seen that hooligan and the rizoma ones. You figure with many bikes using that reservior there would be more.
I'm an exception (or relatively) but I actually prefer the OEM plastic one - as long as it it is clean & shiny!!
The after-market ones just don't look finished to me or that they 'belong' somehow.