DIY design of bbq made from 9kg gas bottle

Whilst doing a lap of Australia last year, we came upon a number of travellers who had made their own bbq from an old 9kg gas bottle.
I am keen to make one myself, and would like any comments and photos if possible.
The ones that I have seen have the top cut off, usually have an opening cut out of the side and some form of air holes around the base.
I have an angle grinder for cutting, but limited access for welding any bits.
I want to be able to use a billy or pan over the fire and have a small camp oven which could also sit in the top.
The units were ideal as they were cheap, compact, mobile and only a small amount of wood/fuel was required.
It is easy to acquire an old gas bottle from a tip etc.