So… far as I know the BeBox is a prehistoric machine; it’s really hard to find, most times I’ve looked on eBay for fun either the price is insane or they’re just not around. There was a thread a few months ago about someone who built a replica with his own 3D printed parts, boards, what not, but I think that was a personal project?
That’d prob be the way, to build a clone with 3D prints and modern parts then put Haiku in it, run BeOS in qemu (I’ve messed with all the images from archive.org; R4.5/Genki and later work in qemu; R3/4 always stop after the bootloader for whatever reason and needed a hack that took me several hours to get them to work; VMware on Mac will run them in black and white).