Note: I missed some complexity above in trying to stop the N-1 being incorrectly "last" above: you can't do that in a pre-hook since in theory a number of pre-hooks could run in parallel and all pass then those updates would be run without constrained order. Some may fail; some may succeed. Still end up with trouble. So, yuck. You don't need a working copy to obtain the contents of a checked in file: you can use "svn export" to obtain the current file. But if you're going to want to update it then, well, yes, you'll need a working copy. Also, just FYI, "post-hooks" are not guaranteed to run. They normally run, but OS shutdowns at the right time, out of resource during fork, etc. can mean they won't. You might want a very simple post-hook to hand off to a queue. Then have the queue do the work using a list. You could even have the queue processor wait some amount of time before doing an update so it doesn't waste effort (of course, nothing is perfect). In any case, when you update the file (lock; update; checkin) then a new revision will be created as well. But you can't guess that the next revision will be Current+1 because, of course, something else could get checked in ahead.
OK, I got it. Actually, CO/CI are made not very often, so I guess it'll be OK with post hooks. First I'll make a simple post-hook logging each CI to a file, then I will know if every hook finished OK. Thank you very much for opening the door wider ;)