logging spammer ips

just wondering if this would be possible w/the current sa-exim 
implementation...

would it be possible to log the ips of incoming mail sources to a 
seperate file?

for example: the originating ip of all spam marked 12+ is added to 
spammer_ips.txt -- which can be used as a blacklist

or, you could log ip:spamscore to one or more files, and play with that 
data

its like making a realtime local rbl

dunno if its entirely useful in practice, but it could be cool to 
experiment with