I spotted some Rare Earth Mag's not too long ago in the wire/cable section of a Radio Shack. I'm not sure what the ceramics go for, but these are certainly affordable. Not sure what JMP used, but the small ones go for $1.79.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F005%5F005%5F013%5F000&product%5Fid=64%2D1895
...and if you can make any sense out of this, here's the specs...
<A HREF="http://support.radioshack.com/support_supplies/doc19/19400.htm
" TARGET="_blank">http://support.radioshack.com/support_supplies/doc19/19400.htm
</A>
I was planning to check these out myself for use on my armor 