Why would you need such a thing? An IR is an IR is an IR...whether it be in a PA28-140, PA34-200T, B200 or a CJ.
Whether you can fly the PA28-140, PA34-200T B200 or a CJ is a completely different matter and independant of the IR.
Firstly, the IR obtained on a single engine aircraft is not valid in a multi engine aircraft.
Secondly, A B200 or CJ require a type rating which includes instrument flight training and the type rating test includes an IR test. Thus at the initial and every LPC you do you are renewing the IR also.
That is the current position.
The reason why I said -
If there was separate IR writtens for SEP, MEP, High Performance/CPL/ATPL, which do you think most people would do and what the costs of doing each would be.
Is that many people claim they want a simple IR when they only want to fly a C172. However, getting what they want may actually make the costs increase and restrict further advancement.
In other words - be careful what you ask for because you might actually get it!
There is of course another option - increase the PPL theory in the appropriate areas and then there would only be the pure IFR elements required for the IR limited to PPL-SEP theory.
Of course then the PPLs who only want to fly VFR complain. It is quite somply a vicious circle.
Regards
DFC