I've just bought one of those. I don't think it is a spacesaver, and sticking it directly to your Arduino board is inevitably a messy solution. If height is really that much of a problem, you might consider a proto shield with the components on the under side.
If height is an issue, get one of the protoboards that don't have the headers soldered on the board, along with male header pins, and F-F jumper cables. For example, in Terry's store:
Then you use the male header pins to attach the protoboard to the Arduino. If possible shorten the legs so you just barely clear the USB adapter. First develop on a breadboard, using the remaining male pins soldered in one end of the F-F cable making it a M-F cable. When you like the design, then move it to the prototype board, soldering the connections directly to the board. I imagine you could solder the components upside down to save a little more space.
The other boards mention look ok, but you are trading width for height, which might be a problem, depending on what size you have to fit the board in.
You can make it even smaller, by eliminating the development board altogether, and making your own system. That is beyond my current skill level, but if you need to slim down that is the way. If you don't need all 20 pins, you can go with other chips with fewer pins.