The EOS-1D X Mark III is starting to show up at different authorized Canon USA dealers — it’s in-stock (with free CFexpress card and reader) for $6499.00 at B&H Photo Video.
This body is still relatively hard to find, so we expect that stock is still limited.
If you’d like to be notified by e-mail when stock is available in the future, you can signup for a notification on the EOS-1D X Mark III page.