Why not create a whiltelist system, like slush?
I think there is one problem, I guess most of the people don't have a static IP. Mine for example is changing every day at 6am. so how would the pool know, that it is still me and would not reject me, because the IP is unknown?
EDIT: the stale thing is weird. I get amazing stale count, but suddenly I get like a burst of stales, for example this just happened:
pool.bitp.it:8334 13/07/2011 21:49:48, d228fc62, _rejected_
pool.bitp.it:8334 13/07/2011 21:49:53, 39d74dee, _rejected_
pool.bitp.it:8334 13/07/2011 21:49:56, 400c5ad2, _rejected_
pool.bitp.it:8334 13/07/2011 21:49:58, e044bf7e, _rejected_
pool.bitp.it:8334 13/07/2011 21:50:07, 658b753c, _rejected_
It happens in random cards and only in this pool.
Except for this "bursts" of stales the stale count is amazing.
I experienced the same. I am using GuiMiner, so I have no exact log, but I saw it live in the stats

happened today at around 0:20am (or is it 12:20pm?) I had about 2-3 stales in a row. between 0:40-1:40am there where 5 and between 1:45-2:00am (UTC+2) there where even 13...

but I guess it was a good day today - 3 blocks found

small reward for the long block

and the hash rate ascends, too - nice to see

cheers iro