The Google homepage integration in Chrome is getting better, the experimental feature has been around for a few months now and it's been improving slowly.
In the latest versions, the Google logo is stored locally, so it's displayed even if you don't have an internet connection.
This is true even if you have a theme installed, as Google's François Beaufort noticed, the simple white logo is used.
This is the logo used on the homepage with custom background images. The custom background images feature has been removed from the proper homepage.
But it looks like those still missing the feature will have an alternative in Chrome, if they haven't started using any of the Chrome apps or extensions that add background images to the Google homepage.
The new tab page with the Google search box and logo is still experimental and is hidden behind the "Instant extended API" flag. The offline/local version is behind the "Local-only Instant extended API" flag in chrome://flags and is only working in Chrome Canary for now.