I would have to figure out how to do it with enough precision. I'm thinking of getting my own case CNCed, but that would be VERY expensive (Still, can't be much more expensive than the higher-end ones on here...
It would be dead simple, just scribe a line from the lower set up to the upper set, tape it off, cut it with a hacksaw or Dremel, leaving a little extra and file it clean to where it needs to be. You aren't cutting around extra keys or anything and you already have points to work from so you aren't working blind.
An hour and a half is being generous if you have any power tools (Dremel) and at $150 per case, you can mess up twice for almost every custom top you have made. Being aluminum you could even have it repaired and try again or fill in the bad spot with JB Weld, paint and resell it for only a small loss.
I could still make it work...but it would be harder...
Harder is an understatement.
No lower case fits your boards controller.
No upper factory case fits your key layout.
No factory plate fits your key layout
Your plate won't fit into any case other than Filco and CM QFR.
It would be $250 for a top IF you design it right to be done cheaply (the longer it's on a mill the more it costs) and then that cost is only if you get it right the first time. $250 should be your minimum estimate... For a top. What about the bottom half? What about the plate? Feet? Nothing off the shelf will work.
What if it takes 3 tries to get it right? Even good cad designers miss things, that's why you have prototypes. You are actually looking at close to $600 for a case, add a couple hundred worth of keys, switches, value of current parts and all told you are quickly closing in on $1000, and that is a best case scenario, with you assembling and painting everything. It could break $1200 pretty easily (how many Korean boards could you buy with that?), and what if something goes wrong?
If you want to keep it at all all reasonable, here is what I would do
Take a Vortex and cut it, it's simple to do. Then take a stock Filco plate and add your necessary switch holes, it shouldn't be too difficult as you have a pattern to work from, just watch the heat, you don't want to warp it (if you want, trim the other holes to allow easy switch removal, again, you have a pattern to work from). For feet, buy some roundbar aluminum off Ebay and make a riser similar to the LZ (my material is on the way and I will document it). You just need a bar with two countersunk holes and two rubber pads. Total cost $13 and half an hour. This part is optional, but I would bolt it together without anything inside, then take a sanding block, belt sander or jitterbug and square everything up (like I did on mine) and then have it painted or re-anodized.
All told you are looking at a half days worth of work, and less than $200 in parts and material. There is no way you will get anything for anywhere close to that. Particularly with low risk. The only thing left is how to account for your controller. If it was me, I would cut a similar shaped hole in the bottom of the Vortex and let it peak through. Maybe add a thin sheet of plexiglass over it with some panhead allen screws.
Start in the morning, you could have the paint drying by dinner, and using it the next day.
