If it had an empty chest the arms would need to be roto with zero articulation(hollow it's no movement). Due to weight and balance. The 43 is a diecast armor. And because the diecast 12 inch figure is over 3 bills alone, with maybe 40% of the surface area HB has the HB is going to be at least double that. So that's a grand almost, for a hollow statue that holds a diecast figure you can't see. And some lights. A two pack with both would cost over a hundred usd to ship most places. Add another 100 for customs/vat/taxes whatever your region has. Or for 30-40% less you can get a fully articulate, properly weighted figure and if you want later get the 43 or 45 or thanos. I mean would u rather have a HB statue and a closeted 43/45 or HB and Thanos (or cap/thor/hawkeye ect) and only be off by 100 or 200(depending on thanos price)?
It's just not possible to make it with another figure in it for anywhere near a price 98% of people would/could pay. I mean you can buy a car for a grand. It ain't a good car. But a running one.
I would be beyond shocked, and really really impressed, if they even could do it.
As for a sideshow exclusive version and a non open one also...never never happen. The sideshow exclusive was a perk given to sideshow to do the distribution job. A way they could be reward and get people to order from them, given the figures everyone was getting (80% of the world anyway) where actually thru sideshow anyway (from SS to the retail stores like BBTS and monkey Depot and black ops and so on). It's a perk. One that requires little cost. Usually no tooling in fact. The luke figure from awhile ago was unique in that sideshow actually had the license and contracted the figure out thru hot toys as a solid for Howard. The vader/luke head was from sideshows molds. So no tooling costs for HT.