First post - I'm Phae Phae on VWVortex.
Here are two solutions I've found:
https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/rmt-100+-mp3-bluetooth-radio/1jm035157at/http://forums.vwvortex.com/showthread.php?7098974-RMT-100-Volk-L-Radio/page2Look at the 2nd post.
I like this radio because it has OEM quality and feel and it has bluetooth and iPod compatibility. This is what I'm going with personally.
http://forums.vwvortex.com/showthread.php?7813513-Eurovan-stereo-upgradesThese are the other components I intend to buy.
The second option would require custom fabrication:
https://youtu.be/xf3qTYYl_gM?t=4m27sThe Sony MEX-GS6
xxBT line of radios seem to support App Remote which allows for an iOS or Android device to be the headunit for all intensive purposes. One could push the single din farther back, put it in the double din middle console if equipped, or somewhere else hidden. Volume functions are available to the iOS or Android device, but I suppose one could always retrofit the steering wheel controls for volume control and radio selection.