If there is an installer for adobe that takes the install from 10 to version 11, then you could create a custom action in your deployment template to push out 11 and execute after the deployment completes. This will ensure that the adobe flash is installed.
The only caveat to this is that the installer has to be able to take the install from 10 to 11. There maybe detection logic in the installer that prevents it, or they may have a single installer per branch (one for 10, one for 11). It would take a little testing to see if the installer works, but a custom action in your deployment template would complete the install for you.
You would want to make sure that you only use this deployment template when you want to do this installation. You would not want to continuously use it and re-apply the same patch over again.
If you need additional information about setting up custom action, please reference our Online Help guide, or contact us directly at 1866-407-5279.