Well, at least I can plausibly go with my second favorite type of helm. And I was so hoping to kill an Englishman and take his sugarloaf... And I wouldn't have to worry about "those ugly SCA faceguards" with a great helm.

The "Heroic Age"-ers will never let me live it down if I wear a Norman.
But I digress. Is there any evidence, either in manuscript or pictorial for the wearing of an aventail or camail with any type of helm? Something like
this. Anachronistic as hell, but helms and maille just look sweet together.
As an aside, can you tell me those sources you mentioned, Swifty? I doubt I can actually find anything resembling a copy of them here in the states, but I've been known to get lucky...