From Homebrewtalk user ctdenney:
I emailed Russian River asking for help recreating their Shadow of a Doubt Imperial Porter and Vinnie just emailed me back today! Unfortunately he didn't have a homebrew formulation for the beer but he gave me the ingredients list and some other details and I'm hoping you guys can help me turn it into a close approximation.
Grain Bill:
2-row
Crystal 75L (that's what I assume he meant by C-75)
Smoked Malt
Chocolate Molt
Aromatic Malt
Special-B malt
Honey malt
Carafa-3 Special malt
OG 1.081 (he gave it to me in Plato: 19.6)
Mash temp 153F
Hops (90 minute boil)
Bittered with Northern Brewer (apparently in interview vinnie has said they add bittering hops for 60 minutes even in a 90 minute boil so we can assume it's for 60 minutes
He said Styrian Golding in the "mid-boil" (maybe 45 minutes?) and at 15 minutes
White Labs CA Ale Yeast