I've been thinking about getting that cable. I already have a 2 headed cable (mini/micro) that I got at the local drugstore, since I have both mini and micro devices, but the Uno has the old USB B connector. Fortunately, I still have plenty of B cables from when that was the predominant cable type for attaching printers and external disks.
If you read the comments at sparkfun, you see that multi-headed cables can degrade the signals in some cases. In fact, after writing this post, I was using the combo cable, and the SD card reader had some errors when I was uploading photos. I unplugged the cable, waiting a few seconds, and replugged it back i, and it worked at thos point. So, it might still be useful to have single ended cables. So far, I haven't found a set of USB cable attachments that would have all 5 ends that I need (USB A male, USB A female, USB B male, mini 5 pin male, micro male). Most of the USB travel kits were made before micro became dominant.