The web's Bauhaus 2 Your House is one of the biggest online retailers of modern reproduction furniture. They self-describe as "the nation's leader in distribution of high quality modern bauhaus classic and contemporary furniture at wholesale prices."
B2H stocks some items and ships others directly from the factory (in Italy), where they're made on demand using a whole lot of leather, wool, chrome, and solid wood. Whichever way you buy, we recommend visiting the product in person first, which happens to be do-able do here in SF because B2H is here as well. This does of course mean that we pay state sales tax, but the extra cost is worthwhile if it means you previewed your purchase. And you can do just that for many items in their catalogue by visiting B2H's local representing showroom, the Malik Gallery. (If there is a specific piece that you're interested in email or call B2H first to see if it's there.)
B2H's list of designers takes in the standard modern biggies from A (Alvar Aalto) to W (Frank Lloyd Wright), with some unexpected appearances from other masterful modern styles and stylists like Art Nouveau, Shaker, and contemporary.
Just how wholesale are the prices? The Mies van der Rohe Day Bed goes for $2,970 including shipping; at DWR the same item is $9,017, without shipping. The marble Saarinen Dining Table is $2,350 with shipping, at DWR it's $2,835 without. On the other hand, the Alvar Aalto stacking stool goes for $289 (shipping included) at Bauhaus vs. $149 at DWR (no shipping).
Which begs the next question: if the prices are generally much lower, how authentic and well-made is the merchandise? B2H says that in a sea of cheap reproductions from China, B2H products stand out for accurately representing the original designs in terms of quality, dimension and scale.