Unless you're doing your own flex, you're stuck with using parts available to be scavenged from KBDs like what I'm lightly modding. Haven't looked at it , but excising the upper part of the case seems likely to work. That would interfere with the KBD/Panel Bezel interface.
Were I you, I'd play with the KBD first as that's the most distinctive feature of your target design. If you can't achieve that to your liking, no point in going farther into the project, no?
edit: the only problem I see offhand if using the likes of my KBDs would be the cursor key cluster. Figure out how to make that look good first off.