We're well beyond the planning stage on this one!
We have created an XML import/export tool that not only handles a store's products but, optionally, all of the data in a store as well (customers, configuration data etc etc). These low-level utilties will give us scope to produce some useful higher-level management functions such as for backups or migrating complete store data sets from QA to production, for example, but these are still being assessed.
I expect that most common will be the usage for product import/export however.
These utilities should be available in the next release.