Google's I/O 2011 has plenty of announcements for Android and hardware support
Reading through the announcements from Google today, it seems like there is a lot of support for Android hardware and connections. Some links are:
The Android Open Accessory Development Kit, which adds support for "external USB hardware (i.e. an Android USB accessory) to interact with an Android-powered device in a special "accessory" mode".
Basically it's USB host mode in Android 3.1.
Android@Home, which allows a standard way for apps to discover and communicate with each other across devices. Of course they are saying that your phone will now be able to tell your washing machine when to run, but who says that your car isn't another device?
More information here.