Reviewing the 2008 BJCP style guide has brought this conversation into more focus for me.
Without knowing the process that created these beer styles, it seems that they are categorized historically and geographically first (hence the German, Irish, British, American, Belgian titles to categories). This takes care of a good amount of beer styles and makes categorizing them fairly easy. However, attempts were made to accommodate more modern styles by putting them into categories of similar beer attributes (lagers, stouts, porters, "hybrid", pale, etc.).
Part of the problem, IMHO, in categorizing this beer is that it inherits historical traits from one category and style traits from another. It straddles the fence between both categories and is therefore difficult to describe and categorize.
Rather than constrain the category because of confusion between it's historical and style traits, a new style should be created that accommodated both aspects of the beer together. I would call it an 10D American (Dark) Black Ale. It would accommodate the additional roastiness of stouts and porters and also the use of American hops for bittering and aroma/flavor. (10C - American Brown Ale is just short by describing, "The dark malt character is more robust than other brown ales, yet stops short of being overly porter-like.") It might also cause the American Stout style to be absorbed into it. The American Ale category looks like it was created to capture all of the American interpretation of certain historical styles. It conveniently captures these styles and leaves room for other American interpretations of classic styles or styles that are uniquely American (as is the case with this nebulous style).
So in the scheme of the larger debate, I don't think the style should be referred to as a Black IPA. It doesn't make sense. I think a new subcategory called 10D - American Black Ale, where dark, hoppy, American-style beers can live, compete, and frolic happily.
But for now, Category 23 would be the best fit, IMHO.