  Relatively recently it was proved that if $\Gamma$ is an arbitrary set, then
any equivalent norm on $c_0(\Gamma)$ can be approximated uniformly on bounded
sets by polyhedral norms and $C^\infty$ smooth norms, with arbitrary precision.
We extend this result to more classes of spaces having uncountable symmetric
bases, such as preduals of the `discrete' Lorentz spaces $d(w,1,\Gamma)$, and
certain symmetric Nakano spaces and Orlicz spaces. We also show that, given an
arbitrary ordinal number $\alpha$, there exists a scattered compact space $K$
having Cantor-Bendixson height at least $\alpha$, such that every equivalent
norm on $C(K)$ can be approximated as above.
