where to buy nice aluminium knobs?

[gcb]

where can I find nice, large, unmarked knobs like old vintage audio gear had?

e.g.
http://www.thevintageknob.org/marantz-PM-80a.html

i'm doing a HTPC build and will use an arduino do simulate the keys and knobs... and i'm badly missing something badass knob caps like those. ideally black anodized Al. Around 3" diam. ...without breaking the bank

Also any hints to other projects using the arduino (or anything else to simulate a HID usb or PS2 keyboard) highly welcome.

thanks!

PS: help save a vintage audio gear from being gutted

[Arrangemonk]

http://www.pollin.de/shop/dt/NTU5OTkxOT ... oepfe.html
http://www.pollin.de/shop/dt/MjQ5OTg1OT ... eilig.html

[gcb]

http://www.pollin.de/shop/dt/NTU5OTkxOTk-/Bauelemente_Bauteile/Sortimente/Mechanische_Bauteile/Drehknoepfe.html
http://www.pollin.de/shop/dt/MjQ5OTg1OT ... eilig.html

Anything in the US? or better, how would i search for them?

I tried to search for the exact measurements from that site (hopping to be a common high-end knob standard), but the closest i got was a site selling amish wodden knobs for kitchen closet doors....