first, points for wanting to make your own costume, more points for making a Bowie-esque jumpsuit.
I was just wondering if anyone had made something along these lines before? (Although I'm quite sure noone in their right mind will have.)
I love jumpsuits. I'm continually designing them.
I've made many jumpsuits, out of different kinds of materials (does that make me not in the right mind?). I made one using a vinyl-coated lycra, which sounds similar to the fabric you're describing. I may be of some help.
I'm not sure if the catsuit pattern will work for what you're describing. Keep in mind that the challenge of a jumpsuit is your pants and top are connected, which means when you bend or sit your top is pulled down, when you reach up your pants are pulled up. I know that sounds obvious, but it really plays an important factor in proper fit.
With a typical catsuit pattern the garment goes over the shoulders (tank or shirt style) which helps keep the top in place. With a tube top style you'll have to give enough ease so you don't completely lose your top when you sit.
p.s. - more points for even knowing what the Mighty Boosh is. my bf is threatening to grow his hair out like that.