(I'm going to be taking a look at a couple of "smarthomephone" options, starting with an odd device from Binatone)
I'm going to start this with a notice - it's so flaky that I have to wonder if there is something physically wrong the unit I have.
The Binatone iDECT iHomePhone 2 is possibly one of the oddest telephony gadgets that has come in to my possession. If you were to take the guts out of an old, low end, Android 2.2 smartphone and graft it into the body of a DECT cordless phone you would end up with something a lot like the iHomePhone.
It runs a fairly stock version of Android 2.2 (though there's no market, not even a third party one, let alone Google Play - so apps need to be side loaded), though it does use ADW.Launcher. The screen's resistive and there's a little stylus that slides inside the phone (you're probably not going to need it to make calls, but it is useful when trying to use the keyboard on the 2.8" screen). When compared to Android based mobile phones, the buttons have to be the second most oddest thing about this phone. It has the sort of buttons you would expect to find on a DECT phone - a green "phone" button, a red "end call" button (that doubles as the "home" button), a D Pad (where up and down are volume control and left and right appear to do nothing) and finally the usual Android "menu" and "back" buttons. However, the most oddest thing about this phone is the phone itself - the screen and buttons are on the back of device with the microphone and speaker on the other side (so, compared to practically all mobile phones, you have to turn the phone back to front when you make a call).
It's dock serves as both charging station and DECT base station. As it's GAP compatible, I decided to pair it up to my pre-existing Gigaset DECT base station instead. One of the nice little features is that it uses the standard Android power bars to display DECT signal strength.
The biggest problem I have with the phone isn't the design quirks. It's the fact that it likes to switch itself off for no apparent reason. Especially during calls. Bit of a fail there. Another, lesser, annoyance is that it's a bit slow to ring. Even when using it's own dock as the DECT base station, other phones will have already rung once or twice before it finally starts to ring.
If it wasn't for that fundamental flaw and it's design quirks it's a really interesting idea for a home phone. You can easily export your contacts from an Android mobile phone and load them into the iHomePhone (even the images that I had associated with my contacts came across). After having become so used to using phones with Android it's much easier to use than the other DECT phones in the house.
There's no built-in VOIP support (which isn't exactly surprising, seeing as it's running Froyo and built-in VOIP support didn't come to Android until Gingerbread). I am tempted to try and install Sipdroid. If I do then I'll write up how well it works.
Of the things noticeably missing number one is SMS messaging. I think it's the number one missing feature because it's a feature that both mobile phones (all of them) and even some DECT home phones have. While I doubt that all that many people use landline SMS, it would have been nice if it supported it.
One other other thing noticably missing is a camera. Probably for a best, if only to stop arguments over whether or not it was front facing camera. This does mean that if the Android based home phone of your dreams is also a videophone, then this is not the home phone for you.