It often can be too early to submit a site to the ODP.
Submitted sites with minimal content can and do get deleted, and sometimes sites get reviewed very soon after submission (this has something to do with the phase of the moon ;) ). If your shopping site sells a highly specialized line of unusual products, showing just a few items should not be a barrier to listing. However, if you are competing with many other sites that carry a similar product line and have extensive catalogs, your site with just a handful of items is likely to be sent directly to the dmoz trash bin.
When I review a recently submitted site with very thin content, I sometimes leave it "pending" to see if anything more develops. However, I feel like the site owner has wasted my time, and possibly lost their best chance at a listing, by submitting prematurely.
IMO, the only time it is to early to submit a site is when it looks incomplete.
Some shops sell very few products, some sites just don't need that much content.
Keep the "coming soon" stuff and "under construction" signs off the site and don't put anything on the site that indictes it is incomplete.
Most any site is always under construction. As long as the scaffolding (sp?) isn't out in the open for everyone to view and the site or store is functional and is what it claims to be, it should be good to go.