I have to agree, regarding the block but, that is where the FE has a advantage, in it's basic, light weight design. Affordable, cross bolted, aluminum blocks, I think would help in extending the FE's longevity.
Regarding the TP heads, I don't think the push rod tube limits them, at all. You can get all the CSA you want with it and you can deal with the tube, in two ways.
1. A airfoil shaped tube, that can also be used to direct flow to advantage how it inters the bowl. A radius around the tube at entry and exit to mitigate turbulence, in those areas.
2. A thin wall behind the airfoil tube, separating the port but, enhancing the flow into the bowl.
It wouldn't look exactly like a FE but, a 3rd option could be a 3 valve head, similar to the Gurney/Westlake. Done right that would be worth at least 50 ci and still have inline valves. Anyone want to round a 385 against that combo?
Another way to get rid of the tubes, would be a timing belt driven, inline, SOHC head, it would be a lot cheaper than the hemi headed "Cammer".