Mention of Twotters stirred the memory somewhat, I seem to think that prop-brakes can be fitted, leaving a running core-engine, and a stationary prop. This would get round the cycles problem, but ground handling would have to be pretty smart on the turnrounds, and maybe there are other engine time constraints/penalties incurred in doing this.
In very cold Polar temps, a volunteer would hold the prop stationary on engine-start, and only let go when a minimum oil temperature was achieved; this could take several minutes, and this and stepping back from the prop on the frozen surface was all rather heroic.
I enjoyed several years flying the Aurigny Twotters in their heyday, but we shutdown the engines after each sector, and the cycles mounted, and they eventually cycled themselves out of viability.
Super VC10.......I have to agree, a twin turbo-Dak has to at least be looked at. (Well I would say that, wouldn't I!).
Aero Mad.......UK CAA were trying to stop Daks from flying pax in the 70's, when I was charged with keeping Intra's fleet passing their C of A Air Tests. They failed to find a good reason then, and this latter-day business of slides, IMHO, has an air of desperation about it, and, more's the pity, successful desperation at that.