Alternatively you could just buy a high quality screen protector.
(Random example : Skinomi are good in my experience and can rather easily make pre-cut custom design, e.g.: for chen's phone)


Correction: a keyboard slider can't be put in an extremely heavy duty backcover / phonecase.

It can but put without any problem in a holster / camera case.

I've been using holsters (normally designed for compact camera) by Hama and Case Logic successfully all the way back from my Palm Pre up to now with my Jolla phone.

They are durable enough that I can safely use them when I go skiing (My week-end hobby is being a ski instructor at the local university).

Though now I'll have to find one which fits chen's 5.5 inch monster.
(The current biggest from Hama is designed for the samsung camera/phone hybrid and only barely fits my 4.5 inch Jolla)
(I think I've seen cases from moleskin that feature attachement points that could be used on the belt).

On PalmOS, it was more :
Alt-Z is "é", Alt-X is "è", Alt-C is "ê", Alt-V is "ë", etc.
Single 2-key combo for most symbols

(It's Palm's webOS that also included a dialog box like the N900.
Sym + letter brings a dialog with all the diacritics for that letter)


Though, SFOS being a Linux, it should probably also be possible to implement a standard UNIX "compose" key :

Compose + e + ' = "é"
Compose + c + s = "š"
Compose + t + h = "þ"
etc.

Note you don't press them as a 3 keys combo, but as 3 keys sequence in order.
It's a bit more cumbersome that a 2 keys combo, but at least it's entirely in-keyboard, you do not need to move your fingers to an on screen dialog.

(As your current PC keyboard probably lacks an actual compose key, check on wikipedia or google which combo is used by you Mac OS or Linux disto. In my case it's Right shift+ Right Control)

If by random chance, one of the OLED manufacturer accepted to provide you a 5.5 inches screen within an acceptable price range, that would be awesome...

(Still I'm paying your future indiegogo even if it's an IPS)

Note: SFOS supports using the volume buttons for shutter if the camera app is open.

Now, regarding a dedicated "shutter" button :
Bonus points if somebody manage to write a patch that :
- if the camera app isn't running
- immediately dumps the content of the sensor in a temp file
- starts the camera app with that file taken as a picture.

(i.e.: being able to instantly capture an interesting moment, right on the instant when the shutter is pressed, even if the camera isn't running).

I second this :
the larger the sensor, the better the quality of the image. (No matter the number of pixels).

(Then second most important things would be quality of the optical part/len).

I think it all boils down to the quality of the keyboard itself.
All the keyboards I've been testing have been "offset" type:

HTC G1 was "meh" in my short experience (my brother used one)
- mostly sort of ultra-flat island keyboard / bordering on the quality of a membrane keyboard.

HTC Dream Z "meh" also (again my brother's)
- same kind of not very responsive keys. also with age, by now, the response of some key has become horrendous.

On the other hand :

Palm Prē and HP Pre³ (my daily driver for long time until HP closed the servers a couple of after having sold to LG) :
- gum drop keyboard (the same kind also found on Black berries, but without the "fret board")
Very nice to the touch, keys very easy to find by touch only, switches are still very responsive even after years of abuse.


So, for chen's phone, in my opion, the biggest influence won't be "stacked / rectilinear grid" vs "offset like a laptop".
But quality of the switching mechanism.

Even the foldable keyboard I own are more quality-dependent.
I still one a few of the original "stowaway" / "think outside" (including a bluetooh one I still use nowadays with my jolla) :
built quality is wonderful, the key still works marvelously even today, even if parts of the case has suffered damage after all this years (the battery cell is naked, cover is broken).

Meanwhile, I've also bought a more recent "Geyes gk108" USB foldable.
It has the same "4-parts W shape" as the older ones (I think I've read somewhere that they've re-used the same molds).
But the choice of component is definitely worse :
key mecanism is much more sloppy, some keys aren't as responsive as others.
(But I still use it sometimes with my Android tablet, because the 10 inch bluetooth keyboard that came with the magnetic case broke).

400-600 € ?

Consider me sold !
(And very likely my brother too, though probably for the android version).