Are you sure that you have to? I was thinking that the limitation was only that a cimena display (or other non-Thunderbolt display) had to be at the end of the chain? As in MBP > TB display > 0 or more Thunderbolt devices > non-TB display via mini displayport.A thunderbolt display HAS a passthrough port that could drive an additional cinema display, but for wonky technical reasons you must have an additional thunderbolt device connected inbetween the thunderbolt display and the cinema display for it to work.
thank you for the link and the info! exactly what i needed!You can connect two thunderbolt displays together to a Macbook Pro. The LED Cinema display cannot be connect unless you have a thunderbolt device such as the Pegasus in the middle. (Thunderbolt display -> Pegasus -> LED Cinema Display.
Read more here: https://www.macrumors.com/2011/09/16/apple-thunderbolt-display-with-multiple-monitors/