Take a look at the "Woodman's Pal". This tool combines the functions of a light axe and a bush knife, as well as having a brush hook blade. The end of the blade is beveled to use a spade.
Like many comprimises, it may not be quite as good as a seperate axe, machette and e-tool, but.....

The Woodmans Pal has been around since the 30's and has extensive use in the military from WWII until the present day. (Question: Does this qualify as "combat grade?)

There are a couple of models and it is available in either 10" or 12" blade lengths. Refer to: www.woodmanspal.com

I've used a 12" blade model for a number of years, including military service, northern canoe trips and around my place. I did make one improvement by grinding off the "safe" end of the edge.
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"There is nothing so frightening as ignorance in action."