Unfortunately no you can't. You can connect one 27" Thunderbolt display to the a Mac mini, then connect another 27" Thunderbolt display to the first Thunderbolt display. However you can not connect a 27" Cinema display to a 27" Thunderbolt display. Reason is the 27" Thunderbolt display outputs a Thunderbolt signal whereas the 27" Cinema display accepts Displayport signals only.
The only way to connect a 27" Thunderbolt display to a 27" Cinema display is to put another Thunderbolt peripheral, such a LaCie Little Big Disk or a Promise Pegasus, in between the Thunderbolt display and the Cinema display. Macworld tested this successfully.
Macworld link.
AnandTech has a detailed review of the 27" Thunderbolt display.
AnandTech link.