Symmetrical Keys - Need Help!

[symmetry]

I have recently had my world changed by a keybaord which has a black key in between every note. Thus the group of three black keys are on the bottom row.
http://balanced-keyboard.com/Graphics/TopKbd725.gif

Now I want nothing more than to have one like this for myself. Most people are modifying a kurzweil sp88x to make a symmetrical keyboard. Problem is that I will be out some $600 in D keys alone. I currently use a Nord Electro 3 HP as my main gig piano. Can I get D keys for this model and make it symmetrical as well?

[symmetry]

Here is another picture https://qph.fs.quoracdn.net/main-qimg-f ... 54bf5d5545

[harmonizer]

This video shows some of the internals of the keybed on an Electro 4HP:
I will guess that your 3HP keybed has some things in common with the 4HP keybed.

If you look around 2:13 or 2:14 and freeze the image you will see some white plastic box-shaped things visible on the left. I do not have an HP keybed in my Electro 3. Maybe these are counterweights? In any case, they have different sizes for the smaller black keys than for the larger-sized white keys. The change you are describing would require moving some black keys to places where currently you have white keys, and vice versa.

At least in the "Waterfall" keybeds (like my Electro 3), there is also some piece of rubber which controls how far down the key can be pressed, and some sort of plastic "catch" which controls how high each key rests when it returns to the "up" position. These are discussed somewhat in a thread on another forum, which discusses adding an additional low E key (a 74th key) to an Electro 3 with the waterfall keybed: http://forums.musicplayer.com/ubbthread ... /2259605/1

These things make me think such a conversion would be very difficult, even on a non-HP keybed.

[CountFosco]

What an interesting concept. D keys are the only keys symmetrical about the centre, but they don't extend to the middle of the C# and D#. Wouldn't there be gaps between every white key?