Nightrider
Clearly as MMEL's are written they give no respect to RVSM/CAT/ETOPS.. ETC. requirements. The governing civil aviation authority that is responsible for the MEL a carrier is responsible to abide by will clearly dictate systems that are required for operational functions such as RVSM... Period.
The manufaturers do though cater to the obvious needs of the above mentioned producing aircraft that are capable out of the box to comply with modern operating requirements.
As of now, besides your oppinion, I know of no authority that requires TCAS for RVSM operation.
Having said that most RVSM airspace is occupied by aircraft that have mode S transponders, it is for the most part a non issue.
Do not take my text out of content.