metal or ceramic foam

> There's absolutely no reason to think that centrifugal force
> wouldn't be useful for making materials settle or separate, and every reason
> to expect that it will be OK for humans (above a certain scale), and will
> prevent the health problems we see with prolonged exposure to 0-G.

Especially since there's no new technology involved! Chemists have used
high-speed centrifuges for decades to make materials settle or separate.
This would presumably use the same technology, just with much slower
rotate speeds (assuming 1G is desired). For that matter, in space the
gravitational force could be adjusted to whatever is ideal for the
construction at hand, something which no land-based manufacturing plant
would be able to do (or at least nowhere near as easily).

Cheers,
--Justin