Dehydration of alcohol
As you've noted, $\ce{P4O10}$ (or $\ce{P2O5}$ ) is a powerful dehydrating agent. According to the Chemical Book, it can actually dehydrate concentrated sulfuric acid to $\ce{SO3}$. So, it's not surprising that it can indeed dehydrate aliphatic alcohols. Using ethanol as an example, ethene can be produced by refluxing ethanol over $\ce{P4O10}$:  

$$\ce{C2H5OH -&gt;[P4O10] C2H4 + H2O}$$  

Note that the reaction will proceed with gentle or no additional heating (the reaction itself is exothermic), it will just do so more slowly.