I finally found some at vitacost, where I do most of my supplement shopping. I got NSI MGC-5™ Mushroom Complex -- 1,100 mg per serving - 60 Capsules for $20.
Supplement Facts
Serving Size: 2 Capsules
Servings per Container: 30
Amount Per Serving
% Daily Value
Maitake Extract (standardized to 30% polysaccharides)(whole fruiting body)
250 mg
*
Cordyceps Extract (standardized to 7% cordycepin acid)(whole fruiting body)
250 mg
*
Shiitake Extract (standardized to 10% polysaccharides)(whole fruiting body)
250 mg
*
Reishi Extract (standardized to 10% polysaccharides)(whole plant)
250 mg
*
Beta-1, 3-D glucan
100 mg
*
*Daily value not established.
Other Ingredients: Kosher gelatin (capsule), rice flour, silicon dioxide and magnesium stearate.