Gun Parts Co.:
Bolt, Bent, Complete, Blue
Listed under 03-A3 with a sort of funky looking sporter safety. They claim to be sold out of "original" A4 bolts - no doubt.
Frankly i only know of one person who is capable of making an authentic looking A4 bolt by hand. He described it as labor intensive and not really cost effective. Most A4 clones (at least the few dozen I have pictures of) use some sort of aftermarket low scope bolt as per the attached link. Real A4 bolts are fairly scare and tend to be expensive.
Regards,
Jim