No, the larger challenges is to make everything fit in an area half the size of a mini tower, make it still look like a radio and maintain cooling under any load.
If they can fit everything into a mini tower, I'm sure you'll find a way of fitting everything into that shelf Radio.
I agree. With careful homework and shopping, I don't see space being a problem. After all, notebooks are much smaller and AiO computers jam everything into the back of monitors. You may need a low profile CPU cooler but they are easy to find. This
Zalman is just over 1" tall. And you may be stuck with integrated graphics, if a low profile graphics card won't fit. Many ITX motherboards use external power supplies so that is not a problem. If going with µATX board, you can use a TFX low profile PSU like this
SeaSonic which is pretty small at only 6.9" x 3.3" x 2.8".
SSDs take up little room and can be mounted with Velcro. So that leaves the DVD drive and there are plenty of slim models that are just 12.7mm (less than 1/2 inch) tall.
Everyone has their hobby. Mine is building computers.
Then we have something in common. And since my first love in consumer electronics was (and still is) audiophile electronics (I still have my Acoustic Research AR-3a Speaker Systems), we may have 2 things in common. That said, my computer builds are more conservative as I use standard ATX mid-tower cases. I get tired of scrapping my knuckles in confined spaces!
And I refuse to go with hand-helds. I have a smart phone but I use it for... what are they called? Oh, yeah, phone calls.
Bottom line here, I will give up my full sized keyboard, mouse and two 24" monitors when I die, and not a minute sooner.