Re: "If high enough they will 'improve' things to prove they are esential to the company,"
Yes, sorry, you are right. Edward Turner. However, I doubt it could have been a Cub frame. The Leader engine is suspended from above and a Cub frame has nothing to hang it from or any obvious place to add the necessary brackets. However, the Leader engine wasn't very wide.
Making a prototype frame in those days was pretty easy - one of the great virtues of non-welded construction. Monel was often used for prototype lugs, the frame could be adjusted on the jig before brazing, and a modified frame layout could be knocked up in a day. Of course, once production tooling was in place, changes became much, much harder due to cost and supplier agreements.
That's the problem with modern cars, bikes and electronics - they are cheap, reliable and all the rest of it, but once a design decision is made it is very hard to alter. In HTC's case, discovering that the pretend buttons were crap a bit late in the production cycle would possibly have involved just too much of a redesign for a company that's struggling anyway. The analogy between HTC and the British motorcycle industry is closer than I realised.