Precision Reloading has new Winchester Industrial 8ga hull back in stock. They must be swedged to remove the band in the brass so they will fit a 8 ga gun. The cost of a swedgeing die set-up is about $400.
Tom Armbrust will sell you Winchester hulls swedged to size for a slight premium over unswedged hulls.
Then you have two options, reload and roll crimp which is very easy to do but slow or purchase a converted MEC press from Ken Burns which is about $400.
I visited RST this early Fall and they were still developing 8ga shells with no estimated availability.