After picking up another Rossi 8320 Author on a whim, I'm also finding myself "intensely interested" in the Author and related shapes, including Squashed Tomatoes, certain variations on the Prince shape, and a couple of oddly shaped Apples...
Brebbia is on the short list, as is Neerup, and there's a Mark Tinsky that was just listed at Smoking Pipes that's quite nice.