Yes, I'm sure that they can be made from bronze rod.  I don't have a lathe to turn them down or bore them out slightly undersized so that they can be inserted then line-reamed to fit.
  The ones I have been using, are manufactured just for the sole purpose of re-bushing throttle shafts.

Not sure about digging up clams, maybe David could answer that one?

Mike B.
  ----- Original Message ----- 
  From: George Wietor 
  To: vanagon@GERRY.VANAGON.COM 
  Sent: Saturday, March 14, 2009 9:35 PM
  Subject: Re: 2.1l throttle plate question

  Can they be made from bronze rod or whatever? Just wondering. George
  (used to dig quahogs and mussels in Naragansett Bay. Probably too polluted or illegal now?
  George in Grand Rapids.

  >   BTW, if anyone can help, I do need to locate a source of
  > the brass bushings, as I'm beginning to run low on
  > stock.  .
  >   I'm not far from you, David.  I work in the
  > Providence area, daily. also.
  >