Hello! I can develop such cron script within two days. Such script:
-- will support creating products with any information that can normally be set via the post edit page;
-- will have a Settings page on Wordpress admin where it can be enabled or disabled, and have its run frequency and path to the CSV file set;
-- will run using Wordpress cron, instead of the system cron - this is more reliable (however I can do it using system cron, if you insist);
-- will import a few hundred itens at a time, to avoid timeouts and interruptions.
I'm a developer with almost a decade of experience, and have worked as lead developer on a media company that uses Wordpress extensively. I'm also quite used to managing servers and, by extension, making cron tasks. I'm likely the most experienced developer within this price range.
I think your needs are clear enough - we will need to discuss only the format of the CVS file and what to do in case of duplicate products. I'll also require access to your server, for testing purposes.
In short, this is the kind of job that I'm used to do, and it would be a pleasure to work with you!
Waiting your reply,
M. Muller