This might be worth considering in a release cycle where we were going to break on-disk data compatibility for some other reason. But I can hardly imagine wanting to do it by itself. Marginal space savings for the "bit" types just isn't that exciting.
Maybe we should start a special section of TODO for "things we might do next time we break data compatibility".
Thanks Tom. So when we say breaking data compatibility, we mean the next release where we will recommend pg_dump/restore right?