Delegate to OS for Rackspace Identity.

But handle the APIKey authentication manually, first.
diff --git a/rackspace/identity/v2/tokens/delegate.go b/rackspace/identity/v2/tokens/delegate.go
new file mode 100644
index 0000000..6a5c1b3
--- /dev/null
+++ b/rackspace/identity/v2/tokens/delegate.go
@@ -0,0 +1,50 @@
+package tokens
+
+import (
+	"github.com/racker/perigee"
+	"github.com/rackspace/gophercloud"
+	os "github.com/rackspace/gophercloud/openstack/identity/v2/tokens"
+)
+
+// Create authenticates to Rackspace's identity service and attempts to acquire a Token. Rather
+// than interact with this service directly, users should generally call
+// rackspace.AuthenticatedClient().
+func Create(client *gophercloud.ServiceClient, auth gophercloud.AuthOptions) os.CreateResult {
+	if auth.APIKey != "" {
+		// Authenticate with the provided API key.
+
+		if auth.Username == "" {
+			return createErr(os.ErrUsernameRequired)
+		}
+
+		var request struct {
+			Auth struct {
+				APIKeyCredentials struct {
+					Username string `json:"username"`
+					APIKey   string `json:"apiKey"`
+				} `json:"RAX-KSKEY:apiKeyCredentials"`
+				TenantID   string `json:"tenantId,omitempty"`
+				TenantName string `json:"tenantName,omitempty"`
+			} `json:"auth"`
+		}
+
+		request.Auth.APIKeyCredentials.Username = auth.Username
+		request.Auth.APIKeyCredentials.APIKey = auth.APIKey
+		request.Auth.TenantID = auth.TenantID
+		request.Auth.TenantName = auth.TenantName
+
+		var result os.CreateResult
+		_, result.Err = perigee.Request("POST", os.CreateURL(client), perigee.Options{
+			ReqBody: &request,
+			Results: &result.Resp,
+			OkCodes: []int{200, 203},
+		})
+		return result
+	}
+
+	return os.Create(client, auth)
+}
+
+func createErr(err error) os.CreateResult {
+	return os.CreateResult{CommonResult: gophercloud.CommonResult{Err: err}}
+}
diff --git a/rackspace/identity/v2/tokens/delegate_test.go b/rackspace/identity/v2/tokens/delegate_test.go
new file mode 100644
index 0000000..c289947
--- /dev/null
+++ b/rackspace/identity/v2/tokens/delegate_test.go
@@ -0,0 +1,161 @@
+package tokens
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/rackspace/gophercloud"
+	"github.com/rackspace/gophercloud/openstack/identity/v2/tenants"
+	os "github.com/rackspace/gophercloud/openstack/identity/v2/tokens"
+	th "github.com/rackspace/gophercloud/testhelper"
+)
+
+var expectedToken = &os.Token{
+	ID:        "aaaabbbbccccdddd",
+	ExpiresAt: time.Date(2014, time.January, 31, 15, 30, 58, 0, time.UTC),
+	Tenant: tenants.Tenant{
+		ID:          "fc394f2ab2df4114bde39905f800dc57",
+		Name:        "test",
+		Description: "There are many tenants. This one is yours.",
+		Enabled:     true,
+	},
+}
+
+var expectedServiceCatalog = &os.ServiceCatalog{
+	Entries: []os.CatalogEntry{
+		os.CatalogEntry{
+			Name: "inscrutablewalrus",
+			Type: "something",
+			Endpoints: []os.Endpoint{
+				os.Endpoint{
+					PublicURL: "http://something0:1234/v2/",
+					Region:    "region0",
+				},
+				os.Endpoint{
+					PublicURL: "http://something1:1234/v2/",
+					Region:    "region1",
+				},
+			},
+		},
+		os.CatalogEntry{
+			Name: "arbitrarypenguin",
+			Type: "else",
+			Endpoints: []os.Endpoint{
+				os.Endpoint{
+					PublicURL: "http://else0:4321/v3/",
+					Region:    "region0",
+				},
+			},
+		},
+	},
+}
+
+func tokenPost(t *testing.T, options gophercloud.AuthOptions, requestJSON string) os.CreateResult {
+	th.SetupHTTP()
+	defer th.TeardownHTTP()
+
+	client := gophercloud.ServiceClient{Endpoint: th.Endpoint()}
+
+	th.Mux.HandleFunc("/tokens", func(w http.ResponseWriter, r *http.Request) {
+		th.TestMethod(t, r, "POST")
+		th.TestHeader(t, r, "Content-Type", "application/json")
+		th.TestHeader(t, r, "Accept", "application/json")
+		th.TestJSONRequest(t, r, requestJSON)
+
+		w.WriteHeader(http.StatusOK)
+		fmt.Fprintf(w, `
+{
+  "access": {
+    "token": {
+      "issued_at": "2014-01-30T15:30:58.000000Z",
+      "expires": "2014-01-31T15:30:58Z",
+      "id": "aaaabbbbccccdddd",
+      "tenant": {
+        "description": "There are many tenants. This one is yours.",
+        "enabled": true,
+        "id": "fc394f2ab2df4114bde39905f800dc57",
+        "name": "test"
+      }
+    },
+    "serviceCatalog": [
+      {
+        "endpoints": [
+          {
+            "publicURL": "http://something0:1234/v2/",
+            "region": "region0"
+          },
+          {
+            "publicURL": "http://something1:1234/v2/",
+            "region": "region1"
+          }
+        ],
+        "type": "something",
+        "name": "inscrutablewalrus"
+      },
+      {
+        "endpoints": [
+          {
+            "publicURL": "http://else0:4321/v3/",
+            "region": "region0"
+          }
+        ],
+        "type": "else",
+        "name": "arbitrarypenguin"
+      }
+    ]
+  }
+}
+    `)
+	})
+
+	return Create(&client, options)
+}
+
+func tokenPostErr(t *testing.T, options gophercloud.AuthOptions, expectedErr error) {
+	th.SetupHTTP()
+	defer th.TeardownHTTP()
+
+	client := gophercloud.ServiceClient{Endpoint: th.Endpoint()}
+
+	th.Mux.HandleFunc("/tokens", func(w http.ResponseWriter, r *http.Request) {
+		th.TestMethod(t, r, "POST")
+		th.TestHeader(t, r, "Content-Type", "application/json")
+		th.TestHeader(t, r, "Accept", "application/json")
+
+		w.WriteHeader(http.StatusOK)
+		fmt.Fprintf(w, `{}`)
+	})
+
+	actualErr := Create(&client, options).Err
+	th.CheckEquals(t, expectedErr, actualErr)
+}
+
+func isSuccessful(t *testing.T, result os.CreateResult) {
+	token, err := result.ExtractToken()
+	th.AssertNoErr(t, err)
+	th.CheckDeepEquals(t, expectedToken, token)
+
+	serviceCatalog, err := result.ExtractServiceCatalog()
+	th.AssertNoErr(t, err)
+	th.CheckDeepEquals(t, expectedServiceCatalog, serviceCatalog)
+}
+
+func TestCreateTokenWithAPIKey(t *testing.T) {
+	options := gophercloud.AuthOptions{
+		Username: "me",
+		APIKey:   "1234567890abcdef",
+	}
+
+	isSuccessful(t, tokenPost(t, options, `
+    {
+      "auth": {
+        "RAX-KSKEY:apiKeyCredentials": {
+          "username": "me",
+          "apiKey": "1234567890abcdef"
+        }
+      }
+    }
+  `))
+}