I also prefer portrait mode in the car. I will buy whatever dock I can find that has the following attributes:
- phone held in portrait mode drops onto fixed MicroUSB connector
- has removable insert / adjustable spacers to allow use with cases
- audio out cable
- docking/undocking needs to be a one-step operation, no latch on top of device
So basically your Galaxy S3 dock, but supporting the bottom of the phone instead of the left side. For me, the whole point of a car dock is to NOT have to plug/unplug a cable. I want to be able to pop the phone in and out easily, and with one hand. If I have to use two hands to plug a cable in, I may as well just use a universal "clamping" cradle and plug the cable in manually. If I'm going to spend $$ on a cradle, there need to be advantages over a universal!
Take it or leave it, but here is my cradle design. If I had the time, manufacturing capability, time, capital, and time, I would just design and sell it myself ...
- Fixed position micro-usb at bottom
- 2 silicone pads on either side of micro-usb connector, vertically adjustable (maybe 2mm total) via plastic threaded rod to allow for different depth cases
- 2 plastic glides (like popsicle sticks) running vertically along the back of the cradle, again with threaded rods to push guides out from back of cradle, to allow phone to align with micro-usb connector on bottom, regardless if phone is naked or has an otterbox type case.
- groove/c-channel side guides that move both forward and back, and adjust for width of phone (trickiest part of design, I can see it in my head but too wordy to put down here).
It might take 5 minutes to set the cradle up for your specific phone/case combo, but once you do it, it's done until the next case or phone of similar design. Do all of that, and I'll pay $80 for it. Make it more adjustable, and it can be pretty universal for most phones with docking on the bottom. Make the Micro USB reversible (pop it up, rotate it 180, pop it back in) for phones that have reversed orientation of the connector.
In the off-chance that you actually use a significant portion of this design, all I ask is that you send me one for free, no royalties necessary