The lovely little Zero4U is exactly the same size and shape as the Raspberry Pi Zero, has mounting holes which align with it, and comes with plastic screws and spacers so that the two boards can be assembled back-to-back into a single unit.
More good news, it connects to the Pi Zero using "pogo pins", which have spring-loaded tips that press against the copper pads on the back of the Pi Zero, so assembly requires no soldering.
To top it all off, it only costs 200 Koruna (about £5.80/€7.40/8.00 CHF)!
I saw something about this device on the web a week or so ago. I was initially a bit skeptical, because I hadn't heard anything about the company or their products before, but after looking at their web page, and reading a few things I could find about them on the web, I decided it was worth a try.
On their web page I also saw that they also offer an acrylic case specifically designed to hold the assembled Pi Zero and Zero4U, at a cost of 100 Koruna. At that price there is no sensible reason not to order a case along with the unit.
I ordered on 2 June, and got an email confirmation immediately. I got another email on 3 June informing me that the order was complete, with a postal package tracking number. The package was delivered to me on 7 June. Oh, and the packing material used in the box was a crumpled-up Czech newspaper! I couldn't be more satisfied with their order processing and delivery.
There is a very good User Manual on the web page, with lots of pictures, specifications, assembly instructions, and an explanation of the powering options for this USB hub. Basically, you can power the hub from the Pi Zero (bus-power mode) or from an external power supply. Bus-power mode is simpler and cleaner because it doesn't require any additional cables or other hardware, but it has a limited ability to power whatever USB devices you are going to plug into it (max. 500mA total).
I found it quite easy to assemble the Pi Zero and Zero4U, you just have to remember that they go back-to-back - there are pictures in the User Manual which show the assembled units quite clearly. The pogo-pins for making the touch-connection to the Pi Zero USB bus are really very clever.
The acrylic case comes as seven pieces - the six sides and a long plastic screw to hold it all together. The assembly instructions are included on the web page, again with plenty of pictures to show what you need to do. The most tedious part of the assembly is just peeling the protective film off of both sides of each piece.
The complete unit, assembled and running with my Logitech Unifying receiver (keyboard and mouse), WiFi and Bluetooth adapters is shown here.
The USB Hub has an LED power indicator (you can see that in the picture), and activity indicators for each USB port. It also has an upstream-connection micro-USB port that you can use to connect it to a non-Zero Raspberry Pi.
One other thing that is worth pointing out for those who are desperate for USB ports on the Pi Zero. Because the Zero4U gets both power and signal via pogo-pin connections, it adds four USB ports without taking away the one (and only) micro-USB port on the Pi Zero itself. If you're really desperate for USB connections, that might be good news.
I have been using my Pi Zero/Zero4U assembly for a few days now, exactly as it is shown above, and everything is working just tickety-boo.
One word of caution about this device - it might not be compatible with the new Raspberry Pi Zero v1.3. Because the Pi Zero board has been redesigned somewhat to accommodate the camera connector, it seems that two of the connection pads that the pogo-pins use have been moved a bit. This might mean that the current Zero4U will not make proper contact. From their description of the situation, it seems clear that they are not having any more luck getting a new Pi Zero than I am... In any case, they say that there will be a new Zero4U model if necessary for this.
In browsing around the UUGear web page I saw that they have a variety of other boards, such as a 7-port USB Hub designed for the "standard-sized" Raspberry Pi models and an acrylic case to fit that assembly.
One last thing. There have been a number of comments about two things that some people think the Raspberry Pi is "missing" - a real-time clock and a complete power-off at shutdown capability. UUGear offers another board called the Witty Pi which incorporates both of those. They also have an acrylic case for this assembly, and even a larger case for the Pi, 7-port USB Hub and Witty Pi all together. Good stuff.