(case-insensitive but case-preserving, as the best filesystems are ;-))
I have a sweet spot for "transformdict" myself.
"Transform" does not remind me of "case-insensitive but case-preserving". If this is important enough to put into the collections module (I'm skeptical), shouldn't that behavior be more strongly hinted at in the name? Lot's of things are transformations. You're interested in a very specific one.