(d@mn edit timeout in these forums)
Here's an apple article on the subject of TB chaining:
Apple Thunderbolt Display (27-inch): Connection options for Thunderbolt Macs
Key portion of that article:
Mini DisplayPort displays will not light up if connected to the Thunderbolt port of an Apple Thunderbolt Display (27-inch). Displays connected via Mini DisplayPort video adapter to the Thunderbolt port of an Apple Thunderbolt Display (27-inch) will not work. Connect Mini DisplayPort displays directly to a Thunderbolt port on a Thunderbolt-capable Mac or to a compatible Thunderbolt peripheral. If the Mini DisplayPort display is connected to a Thunderbolt peripheral, the display should be connected at the end of the Thunderbolt chain.