A simple plank bed from Vivaterra:

Reclaimed Douglas fir Plank bed adds a contemporary green twist to it’s traditional design and honors the character of the rare first-growth fir used in its construction. Up to a century old, the aged wood-from razed buildings-shows off its rich hue, deep patina, and tight grain. The wood is hand-planed to smooth its surface while preserving the distinctive character of the vintage fir’s imperfections. Our bed’s eco-friendly wax finish highlights the wood’s singular beauty. Includes headboard and bed frame. Assembly required. Made in USA. Allow 5 weeks for delivery.

Designing a bed like this is simple as the bed is a no-fuss, no non-sense type. There are no complicated designs, just a simple base support and headboard should do.