I have (on hand) Maris Otter, Columbus, Cascade, Citra, Amarillo, and Zythos hops, as well as a mixed culture of London Ale III and West Yorkshire yeast. Willing to pick up specialty malts only. What do I brew???
Skip the specialty malts and do a nice mixed IPA. The Maris Otter will leave a nice malt backbone to support a hop forward beer. Use Columbus for bitter, citra for flavor, cascade for late, and amarillo for dry hopping.
Sounds good to me. I'd also consider a 2:1:1, 2:2:1 of 3:2:1 (Columbus:Amarillo:Citra) blend of the hops and just use them at 10, Flameout (10 minute stand) and dryhop. MO on its own is great for a beer like this.
I like the idea of a 100% Maris Otter IPA. You could always toast a pound or so of it in the oven or reduce part of the first runnings if you want to change it up a bit.