the split i can't quit

my daily driver at work is a split-spacebar NMB RT8225CW+ "The Right Touch"* which i rubberized years ago to help with touch-typing and make it look a little like a DAS Ultimate (i just love the all-matte-black). i daisy-chain adapters DIN => PS2 => USB and it has performed flawlessly for me. (...although i owe it a new paintjob.) it'll be fine for years or maybe decades to come, but i'm working a bunch at home now too, though, so i need to come up with something similar; i hope somebody here can help me do it (ideally without breaking the bank).
i'm really, truly confused that the split-spacebar/backspace configuration never really caught on. (i guess MightGrowSoft has produced a few here and there, but AFAIK they haven't been mechanical.) why would you waste so much space on a button you only need 1 thumb to press? why would you keep the backspace key so far out of the way that you need to move your hand to reach it? there are a lot of questions, but the bottom line is: for a daily driver, i don't want to compromise on this. i shouldn't have to lift a pinky to delete a single character.
i'm no stranger to soldering components onto boards and so on, but i'm a brand-new dad, so time is at a premium. basically, i'm looking for an end product of "a DAS Ultimate but with a split spacebar" or this cougar thing but with blank keycaps (i do want my numpad, arrows and F keys, but don't need all the other bells and whistles, like USB ports and volume controls and lighting and so on). i use only GNU/Linux, so any reprogramming i can really do from the OS side (although this isn't necessary for the NMB). the infinity ergodox looks awesome and wouldn't be a bad solution, but again, i can't make the time commitment just now.
tl;dr: mechanical keyboard (cherry MX browns), split spacebar, blank caps. does this spark anyone's imagination? thanks for any pointers.

*i realize i should post a pic of my NMB but lemme put a coat of paint on it first.

Nov 29, 2016
you mentioned the dox, which i like, too. But i'm more intrigued by the UHK, can hardly wait for that little beauty i've ordered some time ago. -
Cheers and good luck.