While the wirewrap solution probably meets the OP's needs best, I thought I would mention, I recently bought some mini-breadboards (for use with the UNO protoshield). These don't have explicit power rails, so they will fit in the protoshield, but there are notches on each of the four sides, so that you could have two or more boards attached together to lay out the design. I've seen other breadboards with these notches as well. Here is the ebay seller I bought from, and you can get different number of boards and different colors as well: http://www.ebay.com/itm/3pcs-X-WHITE-MINI-BB170-TIE-POINT-DOVETAIL-SLOT-SOLDER-LESS-BREADBOARD-/271038008650?pt=LH_DefaultDomain_0&hash=item3f1b1fcd4a