(Updated 2016: Matlab now has functions uitab and uitabgroup for creating tabbed panels.)
We have written some code that implements tabbed panels for Matlab. The implementation makes it very easy to add additional panels to an application. It can be downloaded here as pluggablePanels.tar.gz. It includes a README file and a subset of files needed for the example application of an interface for an EEG recording system.
Here is a screenshot:
