I'll add my voice to say MeG is very suitable for solo play.
Although I approach it slightly differently from Simon (e.g. I don't feel the need to keep the cards secret from myself, I just try to make the decisions for each side be based on what they can legitimately see in front of them, combined with the overall plan the are supposed to be working to, sometimes decided by dicing).
If you are interested, I have put up some accounts of a number of solo games, including some of my thoughts on decision making, what makes solo games work/be fun etc....see the AAR sub-forum.