I appreciate your point, but this seems to me like a bit of a slippery slope. As soon as a derivative market based on RNOM16 is created, other traders will want this for USPREZ16 and perhaps for other markets, as well. Your argument that the underlying contract would be difficult to manipulate might be more tenuous in other cases. If a compound derivative market is created, I would suggest careful consideration of the precedent that its rules would set for future derivative markets.
It seems to me that what you're really asking for is leverage. I agree, of course, that the lack of leverage dampens interest in slow-moving, long-term markets. Derivative markets (or, worse, margin buying) would complicate oversight/regulation considerably, though, and even unfounded allegations of manipulation might have a negative effect that outweighs the potential benefit.
On the off chance that you were truly proposing this as an academic experiment on the effect of capital requirements on market efficiency, I would be more supportive if it were implemented in a way that cleanly tested that. At leas then the scandal might be spun into the (questionable) story line that PI is all an intellectual experiment.