Some of the wonderful beers brewed by the Scottish company Innis & Gunn are not too bitter, and one or two on their range might be said to have a slight sweet taste to them.
Likewise, there is a terrific stout brewed by the Belgian company Carolus, which is heavy, malty and quite sweet. Wonderful drinking on a cold winter's night.
Be warned, though. As an earlier poster - velocityg4 - has already point out, some of these are also very, very strong. (As in 6.6% all the way up to almost 9%). That means you will probably have one, at most two, beers, at a sitting.....these are beers to be sipped, slowly and savoured, beers for slow, relaxed drinking.