Be more specific. Do you just want anything single sized that is as hot and dark as you can get? If that is the question, the answer is BC-2. I can't imagine it sounding good in the neck, but it answers your question.
If you want something that is still "traditional single coil" but is as loud dark as you can get, the answer is Virtual Solo for noiseless, or SDS for non-noiseless single.
If your question is "something that still sounds like a neck single coil pickup but is high output and warm-ish" then Injector Neck or HB-2. Injector neck is basically an HB-2 with a more articulate high end, that's why it works better in the neck than an HB-2, which I've found really only works in the neck in very bright guitars/amps and/or with 500k pots.