In a new system - Hasselblad H is the only one left with a single body solution. Can be done with a Hass or Phase digital back, but if you get the new orange square lenses, you'll want the Hass back.
You can do a used Pentax 645N & 645Z or pair a 645AFDIII with a XF and share some glass.
In terms of discontinued or cobbled together solutions, I'm a RZ ProIID kinda guy. Yes, the Hasselblad V & Contax systems are viable, but if I'm going to shoot film, I want an advantage over the digital sensor & the larger negatives would give me that. Picking up my GX680 yesterday reminds me how unfriendly to handhold it was.