I read somewhere that the Roland V-Stands (and possibly their imitators, like Ultimate) always have a permanent slight down angle on the arms. For those with this problem that don't have a wallet as thick as Donny's perhaps it might be worth taking a look at them.

Pretty good cable management and pedal access, too, from what I see....

But I still think that a non-horizontal keyboard is bad for your technique (unless it's higher or lower that normal).