Melissa, if you are not able to find the parts you need locally or on eBay, I have a spare model 12 handle and the beater you need.  However I am in Canada, so the cost of shipping it to you would be higher than within the USA.  I have LOTS of Sunbeam bowl sets, too, but the original white ones that would go with a model 12 are not hard to find.  Keep checking your local thrift stores - they frequently turn up there! 

I don't know if he's still selling parts, but a very knowledgeable person by the name of Dave Harnish (Dave's Repair Service) was rebuilding or making new versions of the ceramic resistors for Mixmasters.  Try reaching out to him - he may have something!

Set yourself up an account on shopgoodwill.com and create a search.  I find a lot of treasurers here and I have seen many Model 12 Mixmasters go for cheap with the beaters bowls and what you could use as a donor handle I bet.

I know there was just one not long ago.  The white ones usually go really cheap.  Even if one is beat up you'll likely still get a good bowl, beater and maybe even a good handle.  

So sorry to see that.  I guess since the items come from many locations it's clear that one doesn't have much experience in packing them.  What a shame.  I've been lucky so far.

I remember years ago I bought a pristine older mixmaster off of eBay.  It had the jadeite bowls and juicer.  Even had the book.  That's how the seller packed it.  I remember when the box was delivered, I picked it up and heard the glass inside and I knew what I was going to find when I opened it.  Everything was broken.  I've since found white bowls for it but its not the same.