Here is a beginning of a rcs plugin that uses rcsmerge, rcs, ci, co and rlog.
I have used it probably over hundred times but needs some work.

<http://www.reedmedia.net/~reed/tmp-sfhkcjkfrfh/rcs.pm>

[[!tag patch]]

> Clearly needs some cleanup and perhaps some of the missing stubs
> implemented, before it can be included into ikiwiki. 
> 
> Notes on individual functions:
> 
> * rcs_prepedit - I'm not sure why you do the locking since the comment
>   notes that the locking does no good..
> 
> * rcs_getctime - You ask why this would be better than mtime. It's
>   because with something like subversion, a file's modification time or
>   ctime is not necessarily accurate WRT when the file was first checked
>   into the repo.
> 
--[[Joey]]

Also here is a quick script to browse the RCS history to use for "historyurl".

<http://www.reedmedia.net/~reed/tmp-sfhkcjkfrfh/rcshistory.txt>