Yes, there are various GUI tools that can control the Pi Camera without having to mess with the code yourself. One such example is PiCameraApp by Billwilliams1952 (available on GitHub). It is described as:
A graphical user interface (GUI) for the Picamera library written in Python using Tkinter / ttk.
An image of the user interface is available here, and it appears to offer options to take photos, record and adjust various other parameters. Sounds like this is pretty similar to what you were intending – even using the same language and GUI toolkit.
Alternatively, there is Pi Vision (also available on GitHub) that appears pretty well developed. This one does allow both photos and (timed) videos to be taken on the Pi.
There are other, perhaps less advanced options available too, such as 'Graphical interface for raspistill' on the Raspberry Pi forums. That particular program doesn't appear to support video recording, but it is relatively simple to use by the looks of it.