http://en.wikipedia.org/wiki/GAM-87_Skybolt
Edit: Even more like the fantastic idea to cancel the wonderful TSR-2 in favour of the F-111 - a decision which was then cancelled later on:
http://en.wikipedia.org/wiki/BAC_TSR-2
""All modern aircraft have four dimensions: span, length, height and politics. TSR-2 simply got the first three right."