If you're looking to accelerate the reactions in the boil, then it would be worth understanding the reaction kinetics (if anyone's actually done that research; it would be rather difficult). I think what a lot of people in this thread are angling at is: Yes, there is no data regarding boil volume, but the fundamentals of chemical reactions are well understood. Vessel volume does NOT have a direct influence on reaction kinetics. The only way it would affect it is via mass flow characteristics (increased the interaction rate of the molecules from differing boil seeding and convection), which is indirectly. This would only increase the reaction rate if the reaction is indeed limited by the work input. However, like most reactions, my understanding is that the SMM--> DMS is an equilibrium reaction, and that the reaction rate is primarily dependent on temperature. (EDIT: Try a pressure cooker to get a higher temperature and faster reaction?)
While I understand you want to (dis)prove your hypothesis, I believe a more holistic optimisation approach would be better.
Eg, you may find that an external boiler with a kettle pump will give you higher energy efficiency and mimic higher boil intensity due to the far greater turbulence. This is in fact how industrial brewing kettles work (they are often under partial vacuum with vapour recovery too).