M2dude
One of the real beauties of the Concorde intake was that it was completely self-startiing, and so unstarts as such were never heard of.
What does self-starting mean exactly? Does it mean self-stablizing?
I seem to remember that Rolls Royce proposed a solution of their own, whre the right hand pair of engines would rotate ant-clockwise (viewed from the front) rather than the clockwise norm for just about any 'Roller' that I can think of. Although this would have completely solved the vibration problem, and was great business for the folks at RR in Patchway (just about doubling the required number of engines) it was a pretty lousy idea if you were an airline and required a much latger holding of spare engines.
Ironically, that idea worked on piston-driven aircraft. The P-38 actually used a left-hand and right-hand prop; in order to make the prop spin in the desired direction, one of the V-1710's were installed backward.