We've not heard of a product named the HP Mini 210 from the company themselves, but a support page on the Spanish HP web site shows 50 configurations for the mysterious device. A system update has also been spotted for the HP Mini 210.
Apart from the different configurations available, there's actually no specifications given, so it may not even be a netbook, but it seems the most likely option. Liliputing suggest it could introduce a significant difference to their current netbook, the HP Mini 110. When further details are known on the device, we'll post the updates.
A post from the Asus Eee PC blog.
Support for unannounced HP Mini 210