My suspicion is that these cats, if they actually get into production (which I doubt), would be rather more expensive than you think.
I don't think they'd be "budget" lenses in the same price band as e.g. the 600/11, 800/11 and 100-400/5.6-8, in fact it wouldn't surprise me if they were "L" standard weather-sealed lenses, with a hefty price tag to match.
I would envisage the primary target buyers as media agencies and paparazzi types, needing highly portable get powerful lenses to capture politicians, "celebrities" etc from a safe distance.
I may have misunderstood your final sentence, but having "donut" bokeh is inherent in the design. The reflector behind the middle of the front element will automatically produce a "hole" in the bokeh.
Having used mirror lenses in the past, I took an instant very strong dislike to the effect. Donut bokeh won't appear in *every* image, but it will be particularly prominent in highlights on out-of-focus marine backgrounds, and that renders it useless (to me) for photographing waders, herons, gulls and other birds that frequent rivers, ponds or shorelines.