Add a function to duplicate a project suite, and save in different location with a different name

I develop tests for 32bit & 64bit applications. A lot of the keyword tests, between application architectures, are the same, the only difference being steps specific to the 32bit or 64bit features.
It's been recommended to develop a separate project suite by using "existing item" for the common keyword tests, and creating specific keyword tests for the different architecture specific features. It seems it is not possible to use "existing item" when referencing a keyword test that launches a "Tested App".
It's more preferential to be able to duplicate an entire project suite and customise the required architecture specific keyword tests and keep a distinct project suite for this purpose.