Ben- I tried to email you directly, but CMU says that is not a valid
email address.

I have used a lot of rigidized over the years- both on architectural
applications like yours, and on sculptures.
There is a lot of rigidized stainless in my camshaft benches at the
Great Mall stop of the San Jose rapid transit-
16 ga stainless is used for the 4 foot diameter ends on the benches-
something like a dozen sheets of the stuff.
http://www.riesniemi.com/pages/pubart_vta.html
A lot of the stainless has been hand textured on my fence for the Del
Mar station on the Pasadena Gold line of the MTA.
http://www.riesniemi.com/pages/pubart_delmar.html
This was mostly done with needle scalers and air chisels, but some of
it was done hot, in a power hammer.

Clients always want it now, and for nothing, and when you are starting
out, unfortunately, you have to take some of those jobs.
But extreme metal manipulation takes experience, time, machinery, and
money. You cant do everything with hand tools by yourself. Interesting
that the big dog architects and the rich clients are always the ones
who want the most, but arent always willing to pay for it. Who else is
gonna do it? There are only a few fabricators I know of who do this
kind of work right, and they charge really big bucks- people like
Metalmorphosis in LA, or Fabrication Specialties in Seattle. If either
of them was quoting your job, you can bet it would be hundreds of bucks
a square foot. And their solutions might include things like casting
the sheet in a foundry.
Rolling big sheets flat again is always iffy- I have done a lot of jobs
where we cut a lot of detail out with plasma cutters, which puts
internal stresses and bends in the sheets- sometimes it can be rolled
out, sometimes not. Back and forth, with a slight curve, seems to work
the best.
Breaking the piece into smaller sections, with the break lines as part
of the design, would help a lot, as those big sheets are just a bear to
work with.

Good Luck

ries