The recent keyboards from _wb_ and ible look pretty good for coding, email and general composition. IMHO though they completely ignore gaming. Let me explain.
Games that use the keyboard (Role Playing Games, First Person Shooters) tend to use either the number keys or the F1-F12 keys or in many cases, both sets. To me, this makes it important to be able to 'lock' the Fn switch in such a way that these keys are accessible without additional modifiers for the duration of the game - and that it is easy to unlock, unshift, unFn - both temporarily and 'locked/unlocked'.
For games, I want all 4 shoulder buttons to be mouse buttons. Mouse 1-4. Think Fire, Secondary Fire, Grenade and Strafe. Despite mapping the mouse functions to the shoulder buttons, I also want easy access to Alt-F3 or Ctrl-F12 or Alt-Ctrl-F7. I.e. the keyboard modifiers are -in the way- if they're mapped to the shoulders. However, they still need to be quickly accessible.
That is why I came up with this rather radical alternate layout. It -looks- like a 'normal' keyboard with the double wide space bar and two sets of Shift, Alt and Ctrl keys. The second Fn key and lack of a dedicated 'caps lock' key will cause some people to do a double take.
http://www.keyboard-layout-editor.com/#/layouts/4562af9f8d20cc476f635615e09965bc
Operation is simple. Press both shift keys and it is the same as pressing 'Caps Lock' on a desktop keyboard. Press both Fn keys and it locks the keyboard into the Fn (Orange here) mappings. Same with Alt and Ctrl. Need to unFn the Fn locked keyboard for a single letter? Press Fn with one thumb (unFn when Fnlocked) and the letter with the other thumb.
It is, by design, a two thumb keyboard. Either thumb has access to all Shift/Ctrl/Alt/Fn modifiers. Modifiers can be 'chorded'. So, if you want to do something as simple as, "Close a window using Alt-F4," on my layout that is -simple-. Chord Fn+Alt with the right thumb and press F4 with the left thumb.
Let's try that on the others presented above...? You'll need to hold down Fn (Bottom Center OR Left shoulder 2) + Alt (Top Center OR Right shoulder 2) + R. The combination makes the Vulcan grip seem easy and requires at least 3 fingers. If you're 'in game' and using the shoulder buttons mapped to the game, this type of combination requires 3 fingers ON the keyboard.
On my keyboard ALL standard keyboard keys are accessible just using two thumbs - and usually with a single or compound action. Need tab? Use either thumb on the Fn key and touch space with the other. Need back-tab? Use either thumb to chord Fn and Shift and touch space with the other. Using chording on the modifier bank allows -any- keyboard accessible combination to be accessed quickly and efficiently.
Let's try another example. Windows users usually copy and paste with Ctrl-C and Ctrl-V. I'm old school and use Ctrl-Insert and Shift-Insert. Try that on the two versions above. Then try it on mine.
Insert and Delete belong with Home, End, PgUp and PgDn. Just look at the little 6 key inset on any proper keyboard. F11 and F12 belong with F1-F10, not relegated off to some alternate key area.
The top center buttons between the nubs are the longest stretch for the thumbs - so they should be 'lightly used' or used for 'system functions'. To that end I have mapped them to:
Esc (Escape), Fn=Keyboard Backlight Up/Down
LCD backlight Up/Down, Fn = HDMI on/off
USB on/off, Fn = 3g/4g (mobile wireless) on/off
WiFi on/off (802.11 radios), Fn = Bluetooth on/off
I'm convinced that I've come up with the most efficient design from a usage and versatility standpoint. It should be the fastest thumb keyboard ever - and it's good for games.
When considering layouts, be sure to throw the 'real world' at them. Include the 'Alt-F4 should be easy to access' test as well as the Ctrl+Ins copy Shift+Ins paste functionality. Consider the keyboard combinations that you use in games you're playing now on your PC - and how often you use the Fn and number keys during those games - and how often you use more than 2 mouse buttons on a modern gaming setup. Loosing the mouse buttons to keyboard modifiers isn't a good option. Having to use 3 fingers on the top side of the keyboard to select a function key isn't either.
The above is in my own humble opinion. I am the proponent of my own design. However, I think it's being overlooked because it is so radically different from the other suggestions. Please give it some usage example considerations - I think you'll like it. Then think about how games will work with it - I think you'll love it.