deskthority

Stabilizers for the longest keys on a standard keyboard add mechanical complexity and create issues (such as mushy or rattly keys) that could all be avoided with adjustments to the layout such that none of the keys would be any longer than a standard Caps Lock key (1.75 units).

How might this be accomplished with minimal disruption to the standard layout, including the standard staggering of alphanumeric keys? Would the spacebar remain an exception, or could it be replaced with two 1.75x keys?

We might start with 60% and TKL layouts, but feel free to tackle full-size keyboards by including the numeric keypad.

well, I tried to do that with Bianca
it's not bad at all if you get used to it

@matt3o, I like your Bianca! This looks close to what I came up with -- splitting Backspace into two new keys, moving Backspace to Backslash, splitting Return and both Shift Keys, and divvying up the Spacebar.

What are your assignments for the 4 keys in between the two Option/Alt keys? Are they all Spacebars? I notice that the one on the far left is marked, hinting at some other function.

the far left "spacebar" 1.75u is an FN key, the others are all spacebars.
The marked 1.75 is a windowed key, simply because I hadn't enough 1.75 keys

most of the additional keys are FN, you end up with more than you need actually

You could have a 14.5 wide layout like Apple does and have a 1.5 wide Backspace, a 1 wide \ and a 1.75 wide Return key. That does screw up Apple's ISO keyboards, though.

Look also at Commodore 64: All keys are either 1 or 1.5 wide. The only stabilised key is the Space Bar.

Standard keyboards are so dumb, as becomes painfully obvious when you ditch the stabilized keys:

My suggestion is to go for something like:

or

if you want to take advantage of your existing muscle memory. (Or with spacebars etc. shrunk to 1.5u to not need stabilizers if you want.)

Better though is to switch to something entirely different (focus on keycap shapes; ignore the legends; mapping of physical keys to output could be whatever you prefer):

It used to be pretty common in the early 80's. I really wouldn't mind to have all alphanumerics 1 units, and all other keys 1.5 units except space... for me personally smaller than 2.25 is a no go.
For example:

with a few more modifiers for modern systems and the smaller spacebar would be just fine.

A non-staggered TKL layout. However the two Shift and Space keys are 2x.