While it is most typically touted as a fully-featured shopping cart system, Magento is an awesome framework to boot. Of particular awesomeness is the layout system. In essence a page is created from "Blocks" which all inherit from an abstract class which does not assume the use of template files. These blocks are assembled according to a layout which is the composition of a bunch of XML files being merged together to describe a hierarchical structure of blocks for each page (inheritance supported for DRY). I love this system but Magento is a very heavy framework.
Are there any other frameworks which use a similar system? I.e. layouts that are defined outside of the template files as described aboive. PHP 5.3 is preferable but would consider frameworks in other languages.
FYI, if there are none that are suitable I'll continue using Magento stripped down to a barebones framework as I have been .