I'm more interested in compounds in 1t to 200t amounts costing <<1M$ (for rockets), and then mass-production of already made compounds would be an innovation.
For instance diasterane and triasterane look interesting but haven't been mass-produced up to now. Stellane may be nice. Is spiropentane, or better its dimer, available in railcar amounts?
Bicyclo[1.1.1]pentane, or better its (preferably unsymmetric) dimer or trimer (and their mixes), is definitely interesting. The precursor [1.1.1]propellane is obtained by photochemical methods, so the oligomer might just be a matter of mixing the propellane with the proper amount of illuminated iodine or bromine, then replacing the halocarbon with hydrogen.
By the way, last time I evaluated the lamp and electricity cost, photochemical synthesis was affordable even for rocket fuels. Since the better (exciplex) UV lamps are rather new, this field can only increase.
For rocket fuels, tertiary amines are better than hydrocarbons and usually easier to synthesize.
Of course, I want aza and diaza-cubane, methylated to be liquid. Obviously.
O yes: a fuel that ignites very quickly in liquid oxygen (trimethylgallium and -aluminium do that) but doesn't catch fire in air (these are pyrophoric). If any possible... Possibly easier, an oxidizer that lights "kerosene" (RP-1) by quickly contact but is harmless.
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Polymers of bicyclo[1.1.1]pentane and bicyclo[2.2.2]octane? The completely straight chains might be stiff and strong, possibly better than polyethylene, today's hi-tech fibre.
Dumb-looking alkanes like CCC(C)CCCC(C)CCCC(C)CCCC(C)CC could make a nice fluid for aeroplane hydraulics and lubricants, electronics coolant, transformer oil, vacuum grease, and so on, if produced in quantity.