Ha-ha-ha!!!
You, guys, drilled the shit out of it. Further modding will be futile, so the only thing I can suggest is take some arts and crafts lessons, practice aerography a bit, and stylize the remainder of that case to look like it's been damaged by bullet holes and shrapnel )))
Regarding the actual case:
1) It's HP's in-house design, so no aftermarket parts will be available on the market
2) Someone suggested getting "used" case, but I doubt that will be possible for such a new machine
3) Replacing the case with an aftermarket model is also not an option, since your motherboard has non-standard size, shape, and power connectors.
So, pretty much you have to ignore everything that's been suggested earlier in the thread, with the exception of "use it as is". Nothing bad is gonna happen if you have a few holes in the case.