For the MudCatters category, I nominate http://ie.youtube.com/profile?user=FrederikSOlesen, the YouTube channel of Freso, which contains and will contain more of solo-performances on harp, bodhrán, bones, spoons, and/or vocals. And it will probably even feature a few non-solo performances as well! (Now, I need to get me girlfriend to allow me to record her whistling, either with me drumming or harping along...)
For the dancing category, I nominate the channels of LeneMads and AneLuise. (And I think I am dancing meself in a few of their videos... can you find me? ;))