Doubtful.
If by "upgrade path" you mean a built in way to upgrade from Windows Home Server 2011 to Windows Server 2012 Essentials, Microsoft doesn't usually have upgrade wizards for their server offerings. Look at the Windows Home Server V1 to Windows Home Server
2011 upgrade process.
If you mean "lower price" instead, Windows Home Server is an OEM/system builder server product, and Microsoft doesn't usually offer discounted upgrades for these products.
I'm not on the WHS team, I just post a lot. :)