John T,
You are correct; the old BCARs required the 7knots which proved somewhat problematic for the B747 as people involved in the original certification programme have told me.
Mad (F) S is on the money. VMCG is a difficult and demanding test point and not every TP will be called on, or permitted, to fly those profiles.
Nick 14, The difference with VMCG and VMCA, or VMCA(2), is that once you are airborne, you are permitted under FAR 25 to use up to 5 degrees of bank which makes a significant difference to controllability compared to VMCG where the aerodynamic controls only are extremely limited in their effectiveness on the ground.
The other thing which is worth mentioning with regards to certified speeds be they VMU which is a datum, or any other speed 'demonstrated' in flight test, and that is we all know the buffers that are applied for the 'average' pilot etc, but every TP not only knows what they are going to do but also they spend a LOT of time and effort at getting those speeds as low as humanly possible.
The commercial success of the aircraft often will depend on the slightest Balanced Field Length calculation advantage over a competitor's aircraft. What I am saying is that with a VMCG close to a V1 (certified numbers), it is most probably circumspect to leave things alone on the operating engine(s) until airborne.