I'll second the view camera with a 6x12 back, it will be cheaper than a purpose made camera and you'll be able to focus via the ground glass and have movements.
And knowing how Will shoots I don't think he'd consider the Holga WPC, I have one and while it's fun for a lark and it's possible to compose pretty well without a viewfinder it won't be anywhere near the sharpness he likes.
But for $50 the WPC can be fun, just don't overlap the frames...
Is your heart set on a 120 pano camera? Because the Fuji/Hasselblad TX-1 is pretty damn sweet, just ask Jannx.