The nat gas version is actually 599 - the Signet 20 is 499, but I'd personally get the 70. The Baron 420 (similar to that 440 up there) is 500 if you want something a bit prettier to look at.
http://www.barbecuesgalore.ca/produc...ron-420-black/
Buy cheap buy twice and be frustrated with the lacking quality of the product in the meantime. Even a thousand bucks for a grill, if it lasts ten years and gives you good results, is a totally fair price to pay in my books. I would suggest not sweating the extra 100 bucks on your price range, that's good value at 599.