I'm also formulating a brown ale recipe myself!
Your recipe looks good for the most part, but here's my 2 cents:
-You have a lot of (dark) crystal in there, 15% of your total grain. The crystal (and especially the Special B) will impart dark fruit sweetness. I would significantly reduce the crystal. Personally, I'd take out the Special B and use 1lb of Crystal 60 or lower.
-I would use English hops instead and probably reduce the IBUs by a tad to the 25-30 range with your gravity.
-I might also reduce the chocolate malt to 8 oz or less. I'm not a huge fan of that malt and it's pretty strong, but that's just my taste.
"In brewing, as in all things, good things come to those who....................................wait"
Secondary: English Barleywine
Bottles: Secret Ingredient #1 (Belgian Trippel), Zappocalyspe (Absinthe IPA)