So I thought I'd have a go making a pinhole camera out of some foam card using the 4x5 film holders I had from a large format camera. A quick google turned up plenty of pinhole build websites out there for inspiration. I ended up using Pinhole Designer which is a pretty comprehensive program to calculate the various distances and measurements you need. I wanted a fairly wide view and according to it a 100mm Focal Length with a 4x5inch filmback would give me a 78° angle of view, which is roughly the equivalent of a 28mm lens of a standard 35mm camera.
Focal Length: 100mm
Film size: 4x5inch
Angle of View: 78°
F-Stop: 222
Optimal Pinhole size: 0.45mm
