The Allak, from Swedish tentmaker Hilleberg, has an unusual configuration: its tent poles support the rain fly, and the sleeping compartment suspends itself from the fly (usually the tent poles support the tent, and the fly clips on top of it).
That first night on the downs I slept in the dubious shelter of a forestry plantation called War Down, tucked into my little bivouac tent while the rain slipped down the conifer needles.