Furniture part identification
The furniture screw connecting bolts appears to be a correct answer but posted in the form of a comment. A quick search for the term results in many ambiguous results, but there are some specific solutions as well. Search for cap nuts for connector bolts:

http://www.rockler.com/cap-nuts-for-connector-bolts



You'll find the same site also carries the bolts in various finishes and lengths:

http://www.rockler.com/connector-bolts-statuary-bronze-connector-bolts