Ah ha. Answered my own question. (Is there a delete button somewhere? Lol)
I did some experimenting, added some easy to find pre and post build events (namely launching the registry editor and notepad..)
In Delphi's bin directory there's a file called CodeGear.Delphi.Targets. Inside that, after the import sections, I added:
<PropertyGroup>
<PreBuildEvent><![CDATA[regedit.exe]]></PreBuildEvent>
<PostBuildEvent><![CDATA[notepad.exe $(MSBuildProjectFile)]]></PostBuildEvent>
</PropertyGroup>
Restarted the IDE, and a new empty project executed those programs on pre and post build. Note that they don't show up on the project configuration screen though, but you can override them, negating whatever was put in the CodeGear.Delphi.Targets file. Cheap, but it seems to do the trick, and you can still override it if needed on a specific project. (Just make sure to back the original file up of course.)