The company would probably have to be near you for them to let you do that and they might want some sort of acknowledgement if the borrowed light is used for a show. Just contact them through their website telling them who you are and what you would like them to do for you.
Usually stuff gets demo'ed at dealers, and big name companies. There isnt much of a chance Strand letting a HS demo a brand new console.
But, the dealers will most likely let you demo new product, with the expectation of you planning to buy a similar product in the near future.
Getting a demo is real easy. If you're serious about wanting to buy the product, but want to check it out first; simply call your local dealer, and tell them just that. In most cases, they have no problem sending out one of their techs with the gear, to set it up, and instruct you on its operation. In most cases you are let run free with the gear for a week or so, to see how you like it.
Only ask for a demo if you are serious about buying the gear. Someone asking for demo after demo without buying anything will quickly catch on at the dealer, and your demo days will be over.
Having said that, if you just want to check out a new piece of cool equipment that has just been released on the market, take a trip to your dealer. Check out the gear in their showroom. Play in their space, on their console and lights for a while. Most shops wont mind at all. The shop I work at loves having guests...lol.