TYPO3 Core

nice catch!
at least from reading there is at least one problem: the previous way takes care about the order of the templates. your patch doesn't!
IMO you need to first create an array as the $basedOnArr and then collect the sys_templates in a 2nd array and then you can run through the $basedOnArr and fetch the according templates from the 2nd array. I hope this is understandable.

Ah, you're right. I missed that issue!
I attached a new patch sys_templates_2.diff which considers the sorting.
I think it's better to let the SQL-Server sort, and not the application... Correct me, if you think your way is better.

ah, didn't knew that way but I don't know if this works with DBAL.
maybe put it into the dev-list for discussion?

You catched me again. I'm pretty new in the core development and missed also that issue. Postgresql didn't support that SQL feature and it isn't used in the whole typo3-src.
Under this circumstances i decieded to follow your first recommendation. This has also the advantage that the database connection is immediately closed after the rows are fetched.
See: sys_templates_3.diff

loooks good now if you change those things to follow the CGL:
- initilize $subrows as array();
- comments should be above and one tab indented
- the continue should be inside { }
- before a { only a space and no tab
- combining strings with . needs always a space before and after the .

feel free to send _4 to the core list (after checking the rules there) and I hope you are not discouraged by my comments

Thanks for your patience and your help. You don't discouraged me at all.
I attached the 13669_4.diff, which follows the CGL.

committed version2 to trunk (rev. 7086).