Here's a thought simon. .
Why not just source the waterproof canvas here in thailand, download a teepee wall/floor pattern and have it stitched up here? Surely, you could do it cheaper than importing them. Last time I checked, they sold paint here too, so you could get someone to decorate the outside with your novel thai cartoon idea. A brief google showed companies scattered all over the country who will sell AND stitch up the canvas in any pattern you give them.
Conversely, if indeed most of your clientele are just lookin' to spend the nite, you could maximize the space with something like this;