I don't think anything like that currently exists. If it did, then it wouldn't be hard to find info about it on here. The closest thing would be the alpine pxa-h701 processor with optical inputs with the rux-c701 controller that fits in a 1 din slot, but that setup doesn't have a radio or cd. Carpcs are a small niche market, and major manufacturers do not cater to us.
"In the beginners mind there are many possibilities, but in the experts mind there are few."- Shunryu Suzuki
"Do it right or don't do it at all"
A separate processor is your only option. Besides, are there any 1-DIN units that do multi- channel processing (AC3 or DTS)? That's the only reason you'd need a S/PDIF input. For simple 2-channel stereo, use the analog input.
I definitely would like to install 1DIN stereo for controlling audio from carpc, as I am looking for one then S/PDIF would be the best option for me, so I run minimal number of cables and shorter distance as analog. Is there any small processor which I could install behind of the head unit, which will split S/PDIF to 5+1 or at least 4 channel audio?
The head unit which I need - should have some basic radio so I can use without carpc turned on on short trips, CD/DVD/MP3 playback is ok but not required, audio volume/mixer is must. Nice if this unit could be a half of deep size then regular so I safe a space behind and better if it looks cheap so no one will like to steal it or has detachable panel.
There was a 1/2 din sound processor-- though I can't remeber who made it, and when it finally got discontinued..(I past saw one in the for sale boards here)
also remember that digital audio is a different setup-- in a car, you are typically duplicating a stereo signal to multiple speakers, where a digital signal is usually used for multichannel surround sound-- so you could run into issues getting all the speakers to work the way you want...
Denon and Clarion both offered SPDIF input head units for use with CD changers. It was an option, so not all have it, but those are the only two brands I am aware of that did.
Please, do tell of the Clarion models that do. I've been a Clarion guru for 16 yrs and I have never seen a single clarion unit w/SPDIF for an audio input, yes they've all been a fiber optic input, but w/a Clarion specific made cable. It was used for DSP/CD changer sound.
I used the DRX9375r along w/the DPH9300 via the optical cable.