[[head-slap]] I'm an idiot! The method that I was trying to add in the body of the init call...
initWithStyle:reuseIdentifier:
...is the one I should be overriding!
Found it here...
Setting style of UITableViewCell when using iOS 6 UITableView dequeueReusableCellWithIdentifier:forIndexPath:
Voting to close my own question. Hopefully though, the brevity of this one will help others avoid reading the superfluous details in the other.