Found eight pieces of three-tie standard gauge track on eBay for five bucks (plus another ten for shipping). While I'm not sure of the manufacturer, it fits perfectly, so it might be early Lionel.
I've seen folks use the center-span exclusively on a layout, Greg. It works pretty well, but you have to have a tailored place for it where it sits a bit below track-level. I took all of the standard gauge off my layout years ago, so this thing, if it ever gets used, will be on the carpet.
The next question is, how do you bend the track-pins so they have the correct angle for each section of bridge/track?