The ruby does indeed run on LGB track - G scale! 45mm to be exact. I have one, and steamed it up this past weekend. It can be bashed to many different styles, it would be entirely up to you.
It is not that hard. If you have the chance, and the patience, get the kit. It is an educational experience, and as long as you FOLLOW THE INSTRUCTIONS and work in a clean workspace (read: perhaps the kitchen table, with a drop cloth over it to make it easier to find parts if you happen to lose one, and so you dont anger the missus with oil stains;)).
It does not take much - a can of butane with a ronson filler valve will last you several runs, a gallon of distilled water (available in the water dept at the grocery store), will go a long way.
check out
www.mylargescale.com/forum - they have forums in various aspects, including live steam.
here's a pic or two of my ruby
http://www.mikewalsh.dns2go.com/RUBY/rrs/ruby1.JPG
http://www.mikewalsh.dns2go.com/RUBY/rrs/rubydouble.JPG
you can tell the difference between my ruby and the stock version.
regards,
mike