They af course available all over e-bay and from many websites. As for finding one kicking around it does happen on occasion. I mentioned not haviing one a while back for my 65 VR and one of the members posted that he had one he could sell but not having any free cash I didn't buy it but someone else did.
If appearance is not important but function is you might try making your own. I think there is an article over on Geofex for making one and basically there are two switches in the unit with one grounded and one not.
Parts to make one would probably be available and you could always use a wood block like some of the amp makers did way back when ( I think Dano did that ).
Of course someone may have one and respond so good luck , hope one shows up.

b
