Let $M^3$ be a three-manifold and consider the representation variety and the character variety of $M$: $$Y=\operatorname{Hom}(\pi_1(M^3),\operatorname{SL}(2,\mathbb C))$$ $$X=\operatorname{Hom}(\pi_1(M^3),\operatorname{SL}(2,\mathbb C))//\operatorname{SL}(2,\mathbb C)$$ I would like to think of these as schemes. They are usually singular; in fact the trivial representation is almost always a singular point.

Are there any known examples where $Y$ (or $X$) are nonreduced as schemes?

I really want to know the answer for $\pi_1(M^3)$; examples with just any finitely presented group would be less interesting.