As of now, the checking for BLE support has to be done manually by studying specifications and searching on Google (as far as I know).
See this question on Stackoverflow: Bluetooth Smart (4.0) / GATT support in Android 4.0?
It states that Android does not support Bluetooth 4.0 (LE) out of the box up to Android-4.0 (maybe with Jelly Bean 4.1 onwards, the Nexus 7 tab suggests that). Manufacturers have to add their own API to allow access to BT LE (e.g. this app is limited to Motorola). That's why your mileage may vary with different phones up to 4.0. Casio's Bluetooth LE enabled watch is also an example of limited (official) compatibility (not even the iPhone 4S is mentioned, by the way).
My best guess is that with more devices having 4.1 the issue will solve by itself and you can find apps showing it.
Here are lists by manufacturers: