Yes. To build a second forbidden palace you must do a few things.
-Click Rename in the Improvements/Wonders Tab.
-Click Cancel in the Rename pop up.
-Now press a for add, or d for delete
-After pressing A, call the Second Forbidden Palace whatever you want to call it.
-Now make it a Small Wonder by clicking its button.
-A menu should now be open to be used in the bottom right hand of your screen.
-Check the box that says Reduce Corruption in the Small Wonder Menu.
-You should note that theres a Reduce Corruption box in the Improvement menu too. You don't need to check this for it to react like the Forbidden Palace, you just need to check the box in the Small Wonder Menu.
-Now you will have to add entries into your PediaIcons.txt and Civilopedia.txt but this can all be learned in the Tutorials/Refrence Guides Forum here -----> http://forums.civfanatics.com/forumdisplay.php?s=&forumid=57
There is also another excellent tutorial in Mizaqs Mod for the MultiTool challenged. It includes a scenario that has a lot of empty units/improvements/techs you can modify to become whatever you want. I didn't use the scenario but the Readme is very well written to extract the info you want on a timely basis. You can find it here ---> http://forums.civfanatics.com/showthread.php?s=&threadid=16406
Hope this explains it all for you