Sounds to me like what the D300 shooters would be satisfied with is the D7100 innards placed into a D300s body, but perhaps with the D7000 16.2MP sensor, so that they can have 8-9 FPS (which is the only way you're going to get it).
Maybe Nikon should just do this, and charge $2,000 for it, and we'll have peace in the valley again. How much R&D and retooling is needed for this? It sounds like the only issue D400 wanters have with the D7100 is it's not in a big, manly, "pro" chasis with the same controls as a D4. I say, give us our Corvette with a V6. In fact, other than the desire for the higher FPS and an AF-On button, I've heard very few IQ/performance critiques of the D7100 as it relates to photographic needs.