As others have already said, I would strongly advocate for an FC660C or FC660M (I own both).
The "C" is Topre, and unfortunately is not easily customizable. But it has this very pleasurable Topre signature "Thock".
The "M" has Cherry MX switches (different kinds available), and you can easily find keysets for it: all the keys are standard except the right Shift (it's the same as the left one), and the Win (Meta or Super) key, which is 1u wide (not hard to find).
I know some people dislike the shape around the Insert/Delete key island, but for me it's a valuable feature. Remember, your hands don't see. The right part of the keyboard is actually very well done, as it allows to find the navigation keys easily, by touch. It's something that you should not underestimate. I have other keyboards with more compact layouts and I am always annoyed by the fact that the navigation keys are lost in the pack.
Needless to say, the build quality is very good. You will have to work hard to get the same quality on a DIY.
