Cyrus imapd supports exporting/importing emails through NNTP. Currently there is no useflag for activating this option. Please, add that flag. It is only about an additional 'configure' option. Thanks.
Created attachment 84911 [details, diff] cyrus-imapd-2.2.12-r4.ebuild.patch Here comes the patch to enable NNTP.
Fixed in 2.3.7, thanks.