Hermon Welcome to DC...
Don't know if this qualifies as a frosting, but I like this. It may be more of a glaze. Amounts can be adjusted to make more or less.
3 Cups Powdered Sugar
6 Tbl Milk
1 t. of lemon juice
1 stick of butter
Melt butter, add milk, lemon juice, and sugar. This will be somewhat thin and can be spooned over the cake to form a glaze. For me it is a good balance of sweetness, vs. the tartness of lemon. I hope this gives you some ideas.
Have Fun!