One of the premier vintage slide guitar companies is National Reso-Phonic. National is a manufacturer of resonator guitars, which uses metal in replace of wooden sound boards typically found in acoustic guitars. National was founded in 1927, and still exists under the National Resophonic name. The guitars are typically found in bluegrass, blues and country, and are extremely collectible and sought after.
One of the problems Vintage Guitar collectors face is pricing guitars, especially when they're ultra rare and there's very little to compare a price against. Luckily, Vintage Guitar magazine publishes each year, an official price guide that includes historical date, realistic market prices on thousands of vintage guitars, amps, basses and other items as well. They've been tracking vintage guitar sales for years and truly has the more comprehensive price guide out there.
Their latest 2011 edition just hit the shelves. The guide tracks 1,800 brands supplemented by 1,100 photos and is truly the most accurate price guide for vintage guitars that you'll find. This guide is perfect for tracking your own collection or having something to compare against for your next purchase.
Amazon a great deal on this book, with a huge discount off the retail price! Check this out! It's a deal for any vintage guitar collector!