Is it possible to automate material creation with new textures?

Sure, just use a script like this:

 // CreateMaterialsForTextures.cs
 // C#
 using UnityEngine;
 using UnityEditor;
 using System.Collections;
 using System.Linq;
 
 public class CreateMaterialsForTextures : Editor
 {
     [MenuItem("Tools/CreateMaterialsForTextures")]
     static void CreateMaterials ()
     {
         try
         {
             AssetDatabase.StartAssetEditing();
             var textures = Selection.GetFiltered(typeof(Texture), SelectionMode.Assets).Cast<Texture>();
             foreach(var tex in textures)
             {
                 string path = AssetDatabase.GetAssetPath(tex);
                 path = path.Substring(0,path.LastIndexOf("."))+".mat";
                 if (AssetDatabase.LoadAssetAtPath(path,typeof(Material)) != null)
                 {
                     Debug.LogWarning("Can't create material, it already exists: " + path);
                     continue;
                 }
                 var mat = new Material(Shader.Find("Diffuse"));
                 mat.mainTexture = tex;
                 AssetDatabase.CreateAsset(mat,path);
             }
         }
         finally
         {
             AssetDatabase.StopAssetEditing();
             AssetDatabase.SaveAssets();
         }
     }
 }

Keep in mind this is an editor script and need to be placed in a folder called "editor". Once you have this script in your project and it is compiled you can select one or multiple textures in your project panel and then click "Tools->CreateMaterialsForTextures" in the menubar.

Note: if the script just was compiled the Tools menu might not be visible yet but when you just click any menuitem it should appear.

This script will create a material next to the texture with the same name. However if there is already a material with that name it does nothing.

edit
Here's the same script but turned into a wizard which allows you to select a different shader before you create the materials:

 // CreateMaterialsForTextures.cs
 // C#
 using UnityEngine;
 using UnityEditor;
 using System.Collections;
 using System.Linq;
 
 public class CreateMaterialsForTextures : ScriptableWizard
 {
     public Shader shader;
 
     [MenuItem("Tools/CreateMaterialsForTextures")]
     static void CreateWizard ()
     {
         ScriptableWizard.DisplayWizard<CreateMaterialsForTextures>("Create Materials", "Create");
 
     }
 
     void OnEnable()
     {
         shader = Shader.Find("Diffuse");
     }
 
     void OnWizardCreate ()
     {
         try
         {
             AssetDatabase.StartAssetEditing();
             var textures = Selection.GetFiltered(typeof(Texture), SelectionMode.Assets).Cast<Texture>();
             foreach(var tex in textures)
             {
                 string path = AssetDatabase.GetAssetPath(tex);
                 path = path.Substring(0,path.LastIndexOf("."))+".mat";
                 if (AssetDatabase.LoadAssetAtPath(path,typeof(Material)) != null)
                 {
                     Debug.LogWarning("Can't create material, it already exists: " + path);
                     continue;
                 }
                 var mat = new Material(shader);
                 mat.mainTexture = tex;
                 AssetDatabase.CreateAsset(mat,path);
             }
         }
         finally
         {
             AssetDatabase.StopAssetEditing();
             AssetDatabase.SaveAssets();
         }
     }
 }