That's actually exactly what I plan to do. Great minds think alike. It's too bad about the front and rear sights though, poor design if you ask me. Making those fixed to the receiver probably wasn't necessary. But it almost looks like they can cleanly be removed, I could be wrong though, I'm just going off observations of photographs taken in low light.
Time will tell. If they can't be removed without literally hacking them off, it may be easier to build around them by altering the lower and enhancing the cheek weld of the gun and then just changing the aesthetics of the upper. Not ideal either really, but for the less technically inclined it may be a better solution. But first thing I'd do would be to make an ambidextrous mag release, that button is tiny.
