Thanks for the tips. I'm hoping to purchase something and not rent it. I kick myself that I hadn't thought of movie costumes sooner as there was a nifty space suit from the film "Supernova" up for auction just a month ago. That would have done the job nicely.
If I am creating my own helmet, what's the typical method used for a clear visor? I've done a lot of mold making and casting, but I assume a visor would best be vacuum formed from some heat-pliable material.