Here we have a nice original un-restored Lambretta LD right now on ebay. There were a ton of these things sold in the US, but you just don't see too many of them on the road, or at rallies. I think they have some of the same issues that keep the 50's Vespas in garages... mainly that they are slow and have terrible lights. However, I would say that the 50's Lambrettas are more competent scooters than the 50's Vespas. Nevertheless, it is hard to drive a scooter that tops out at 45 mph on today's roads, that's for sure.
This one is a real time capsule. A "barn find" in the best sense of the word. You just don't find them like this much anymore. It has original paint, and essentially looks like it has not been touched since it left the factory. The "buy it now" price is a very reasonable $925, but you have to pick it up in Baltimore or Washington D.C. For someone in the area, this will be a scooter that will be well bought. It will certainly require a lot of basic TLC work to make it a reliable runner, but it is a great start. Personally, I'd spend a weekend getting it running well, and then drive it as-is. Eventually, I'd put a 150cc top end on it, but that would be about it. With about $500 worth of parts, this would be a great neighborhood run-about.