Timber coping?
 

I've nearly finished building a timber-framed front porch, which will
be clad in cedar. There's a low parapet forming the outside of the
tray that forms the flat roof; I want to fix a fascia to the front,
overlapping the cladding, and put some kind of coping over the top
(rather than have roofing felt visible). Does anyone know if there is
a ready-made moulding for this? Ideally it would be at least 6 inches
wide, with a fall to each side and a drip groove on each side - a bit
like two window cills, back to back.

Cheers
Richard