[hatthew]

I solved it with this, a pleasingly symmetric solution. I was surprised that a solution exists with all the queens in a row.

    . . . . . . . .
    . . . . . . . Q
    . . B . . . . .
    . . . . . Q . .
    . . . . . . . .
    . . . Q . . . .
    . . . . . . . .
    . Q . . . . . .

[aidenn0]

More surprising to me is that there's a solution with no pieces on black.

[archargelod]

I found this solution (actually, it's 4 solutions, each B is a different Bishop placement and at the same time it's the only 4 spots on the board not covered by queens):

    . B . . . . . .
    . . . . . . Q .
    . . . B . . . .
    Q . . . . . . .
    . . . . . B . .
    . . Q . . . . .
    . . . . . . . B
    . . . . Q . . .

[js8]

I started with 4 queens placed symmetrically on c7,g6,f2,b3, which covers everything except corners. Then I shifted all of them diagonally, i.e. to d6,h5,g1,c2. And it turns out, then only a8 and b7 are not covered, which can be easily solved by placing bishop anywhere at diagonal, e.g. h1.