I don't think you can get a Munechika Sword yet, as the hilt isn't in the game, even if the other components are. I had several of the sheathes, but vendored them to make room in inventory.
The others aren't bad, really. My preferred weapons are water gun (came from an event in the summer) and cursed nameless sword (from farming opponents in campaign map 6-4). Well, I don't have a cursed nameless sword yet, but I plan to get a few eventually.