I have a pair of partially fabricated brackets that I was going to use with a split front wishbone on my speedster but ended up taking a different approach. They measure approx 7 3/4" x 4 1/2" made of 3/16" thick steel. You will need to add gussets and mounting hardware, but this will at least get you started. Free to whoever wants to pay shipping. Thanks for looking.
I would use these on my speedster if not already claimed.