here's a link to plans and more info on top bar hives from Philip Chandler
webpage
We used to keep bees in wooden hives, but top bar hives seem less invasive to both bees and your wallet! If you're using plant stems for the top bar, be aware that size matters! if it's too narrow, or too wide, you can end up with the combs connected, which makes harvesting much more difficult. There is a specific 'bee space' that helps stop this happening, and varies with the size/type of bee you're keeping.
Re straw and bramble hives: I've had a go at making one and the hardest part is tracking down the long wheat stalks that were traditionally used. You basically stuff the straw through a cone whose mouth is the diameter you want for the rolls of straw, then sew each coil to the previous row. I'll look out some more pics, but this is an old Normandie 'ruche en paille' aka (UK) a 'skep' we happen to have hanging up in an outbuilding. We used ours for capturing swarms, and as far as I know you wouldn't generally use it for a colony as you can't easily harvest honey from them. I am almost certain that in times gone by they destroyed the bees in the taking of the honey from these hives.
You could make a cut down version of a top bar hive and attract a swarm f.o.c. April/May is the European season for swarms, and I still haven't got my hive made yet! Ah well, maybe next year?