Picture a free-standing bookshelf-type of unit, but instead of open shelves, there are slats making separate jar-sized pockets on each level. The side boards have rounded bottom ends, or are hinged. Fasten it to a reciprocating arm or belt drive, operated by a geared down small-but powerful electric motor (or even windmill if you are a 'green' purist). As the thing moves back and forth, the jars of tincture are shaken 24/7. the only odd bit is the jars on the shelves towards the top are shaken with more gusto than those on the bottom. Only a slow back and forth movement should be needed. The contraption just described could probably be constructed inexpensively, by any backwoods mechanic or farmer (I think).
Summary: If you can't picture how this works, then imagine a free-standing book shelf unit with jars on the shelves. About 5' tall, 4' wide, and 11" deep. The bottoms of the sideboards are rounded. You hold the top and rock it back and forth, 24 hours per day (or rig as described above if you have other things to do!)