Custom mesh in material preview

Sometimes it would nice to evaluate material previews on the real thing but quickly as in the preview panel. So a button for "active object" would show the material preview using a custom mesh. Then also a slider to rotate the mesh would be nice... and I'll stop it here, or the list of feature may grow out of control (lights control? ground glossyness? zooming?...) As always, an image explains it better than my texts...