We've seen a guitar meets Wiimote hack before, but while Rob Morris only straps the two together, Ozan Sarier's Wiitar is an all-out amalgamation.
It's a dissected Wiimote installed inside an Ibanez RG Series electric. Carve out "the middle section between the tremolo cavity and the electronics cavity" and apply some soldering iron skill. Ozan's posted a buildlog if you fancy attempting this yourself.
Unfortunately there's no video of the Wiitar in action, so we're left imagining what it sounds like.