June 2014:
Thanks everyone for the answers. Just to update, as of June 2014, BLE Peripheral mode is offered in the Android L Developer preview. So now Android devices can act both in peripheral and central role. Hope to see it in the Android L
official release. Quoting from their blog New in Android: L Developer Preview and Google Play Services 5.0:
The L Developer Preview, lets you explore many of the new features and capabilities of the next version of Android, and offers everything you need to get started developing and testing on the new platform. Here are a few of the highlights for developers:
BLE Peripheral Mode — Android devices can now function in Bluetooth Low Energy (BLE) peripheral mode. Apps can use this capability to broadcast their presence to nearby devices — for example, you can now build apps that let a device to function as a pedometer or health monitor and transmit data to another BLE device.
Update 16th October 2014:
Its out now! Checkout Android 5.0 wireless changes page.
Update 8th December 2014:
The bad new is that BLE Peripheral mode will only work on the newer Android devices (as per the date), viz Nexus 6 and Nexus 9. It won't work on Nexus 4/ Nexus 5/nexus 7/ nexus 10 even if you update it to Android 5.0. You can read the comment by one of the Android Project manager on BLE advertise mode not working ticket. He says:
We introduced BLE peripheral mode in Android 5.0 Lollipop. Nexus 6 and Nexus 9 are the first two production Nexus devices that support BLE peripheral mode. Due to hardware chipset dependency, older Nexus devices (4/5/7) will not have access to the feature on Lollipop.
Thanks to Rob Anderson for informing.