I know it is pedantic but:
I agree with an IR or IMCR the in sight of surface rule etc disappears but you have to be under on of two flight rules.
If you are not in sight of the surface at or below 3,000 feet you cannot be VFR (because I thought the rules say so). Obviously you are legal because you have an IMCR or IR and you are also in VMC becasue the base is beneath you but surely you must be IFR even though you are in VMC?
In the same way if you are only 800 feet above an undercast whilst VMC and legal because you have an IR or IMCR again at any level surely you must be IFR because you are not withiin the vertical seperation for VFR.
In other words to answer the original question the only correct answer is you are IFR unless you also meet the VFR criteria - at or above 3,000 feet and meet the vertical and horizontal seperation requirements
I agree you might well want to tell the controller you are IFR but VMC.