Not certain where to post this but here we are.
This is the first forum I've managed to get some assistance from, so it seems fair I contribute some work to make everyone elses life easier. This is an XML schema file that will power the intellisense of your XML editor of choice and make your UI modification a whole lot easier.
You can refer to the project page for details and a link to the file.
SC2Layout XML Schema
PS. I uploaded the schema as a TXT file because Hive does not allow XSD. If you have any recommendations on how I can upload it as an XSD, please give them to me!