Thanks for pointing that out! I also had something similar in mind.
Instead of loading a big file of say 2hrs to the server load chunks of the movie (of say 1 minute each -> 120 files) to the server, then use php to find the appropriate file to start on (if the "streaming" is ought to have started X-30 minutes ago, start with chunk 30).

Something I'm not entirely sure about is how the player would harmonize with this kind of strategy. Would it start rebuffering after each minute/chunk? Or will it keep polling the php script and therefore prefetch the binary of the next chunk? Would the php script have to modify the header information of each chunk so as to have a continuous stream (continuous file stream [1 header per stream] or several sequential file streams [one header per chunk/file]).

The idea of creating chunks instead of having one huge file may make the idea of "live streaming" sound much easier but I'm not sure if this is truly the case. I believe that the JWPlayer will simple buffer the contents of the current chunk N and then play it (and not automatically start buffering the following chunk, i.e. the script will only invoke the php script once).

Did I understand your suggest correctly?

Thank you once again for your input,

Laurent