Recently i have been looking into non-mini engine conversions and whilst browsing a few sites i found many weird and wounderful custom made roll cages. I have no rear seats in my car and its of a stripped out nature so as long as there is enough room for a driver and pasanger everything will be peachy. I would idealy like door bars and a dash bar. i would also like 2 rear diaagonals to meet in the bacl of the car to make a X type shape and i would also like to do this above the front seats.

I would really like to get some thing looking like the above, i mean you dont see it to often. But what kind of things will i need to take into consideration when i do some thing like this? I dont want it up to any outstanding quality and supreme strenghts but i would like it to withstand a good woolop on the road.
Thanks, Tomm