Where to buy; 

Acoustic Music Works  New and occasionally used Stiver mandolins.  

Here is a video of Gordon Neidinger playing a Stiver two point mandolin; http://www.youtube.com/watch?v=Pt1LUoLgZek&feature=youtu.be

Elderly Instruments  New, and occasionally used Stiver mandolins. 

Links to performers web sites that use a Stiver mandolin; 
This list is only of the sites that I am aware of at the present time. It will be added to as I learn of more.

The Wildwood Express  (Lou Stiver plays in the Wildwood Express bluegrass band.)

Jesse McReynolds And The Virginia Boys 

Great American Gypsies  

The Bluegrass Mountaineers  

Well Strung 

Pittsburgh Mandolin Orchestra 

New And Used Bluegrass 

The Slocan Ramblers

Other links; 

James tailpieces are used on new Stiver mandolins. 

Tone-Gard  I use a Tone-Gard™ on my mandolin and highly recommend them.

Stiver Mandolins contact;  lstiver@twc.com