Just dumped a prototype of the Famicom version of Rampart. Note that the Famicom version is a totally different game than what was released on the NES internationally: the FC version was ported by Konami!
This sample is similar to several other Konami FC samples that have been located, in that it lets you play a small portion of the game before cutting you off with a "Coming Soon" message. These were probably used for store demos and the like. More details are at
http://hiddenpalace.org/Rampart_(sample)