Reflexil already works with Cecil Studio:
Cecil Studio was a "test project" made by:
Jb Evain (Mono.Cecil, Mono.Cecil.Decompiler)
Sebastien Lebreton (Reflexil)
Patrice Lamarche, Robert Pickering, Vincent Bourdon, Romain Verdier & Mathieu Szablowski.
Sebastien Lebreton also made the Cecil Studio plugin API which is very close to the Reflector API. Should be very easy to convert existing plugins.
That's why Reflexil runs both on Reflector and Cecil Studio.