It would be nice if all of dpkg's safe I/O code invoking fsync and
friends would be disabled during installation. From what I remember,
dpkg's --force-unsafe-io disables only some of them.

I think it would be possible to either use the eatmydata wrapper or
convince the dpkg maintainers to introduce a --force-really-unsafe-io
option that disables all fsync calls. (The additional option in dpkg is
probably the cleaner solution.)

Ansgar