Are there any IFR-certificated and equipped aerobatic aircraft?
Yes: Consider the Zlin Z 242. The type certificate shows that it is certified in the Acrobatic, Utility, and Normal categories. In the section for Optional Equipment, the aircraft can be sold with 


  Communication and navigation equipment VFR DAY, VFR NIGHT OR IFR according to actual requirements of the customers 


Generally, if the aircraft meets the minimum equipment requirements and inspections, and the POH, Type Certificate or other manufacturer's documents allow it, an aircraft may be flown IFR in IMC.

There would be no particular limitation on operations specifically because the aircraft is capable of aerobatics, but the pilot would still need to follow their clearance. This would significantly limit the benefit of the instrument certification. (Note that even if deviations in altitude and flight path were approved, aerobatics still wouldn't really be possible.)