I have written a patch to provide a new OS native sockaddr type (called apr_os_sockaddr_t).
The new functions apr_os_sockaddr_get() / apr_os_sockaddr_put() allow to convert from / to the apr_sockaddr_t (like apr_os_socket_t / apr_socket_t conversion).

Unlike apr_sockaddr_t, this "serialized" type can be placed in shared memory for multiple processes to use it.
I find it very useful for an apache's mod_proxy patch I'm writting (and submitting to dev@httpd), where the current backend address is updated according to a TTL parameter (and shared between the children).
The sockaddr info has to be in the scoreboard for this to be feasible.

Finally, the patch also provides a apr_sockaddr_dup function which is terribly missing (IMHO), one may want to copy an address from a pool to another without a new DNS lookup.

The joined patches are for trunk and 1.4.x.
Thanks for your feedback,
Yann.