Trying to study more on this and turns out that it may very likely not be the Yoshida Brothers. I've been seeing a couple of leads that point to another
shamisen duo (or taiko drummers?) called Aun (looks like that was their starting name then changed to Aun J Classic Orchestra). I've only been able to hear one of their tracks through this one youtube user -> By Popular Demand - My Intro Song - YouTube (
http://www.youtube.com/watch?v=EZnqY0Hy6wc) . While this isn't the right track, it does sound like the same kind of production quality to me. I've been trying to look for some their other tracks to sample but it seems I can't find anything else on these guys :sad: I'll keep looking a bit more...
--- edit
I found the entire bit put together with location/credit roll and it does indeed say Aun ->
http://www.youtube.com/watch?v=eX_rECldlmE&feature=related
A step in the right direction.