Regarding .pos, use $fopen(name|N).pos, it's the same thing.
As for the .line property, mirc would have to count and keep track of all the $crlf's in the file (until the current .pos) to get the line number. Apart from having a significant impact in performance, I'm not even sure it could work correctly, since counting the $crlf's would mean moving the read pointer around behind your back.
