bmesh py api:

Wrap customdata, so far you can access the data layers in a pythonic way but not manipulate the customdata yet.

provides dictionary like access to customdata layers, eg:
  texpoly = bm.faces.tex["UVMap"]
  print(bm.verts.shape.keys())  # un-intended pun, keys() works on all layers.
  print("MyInt" in bm.edges.int)  # __contains__
  layer = bm.faces.get("CheckForLayer")

source/blender/python/bmesh/bmesh_py_api.c

@@ -35,6 +35,8 @@
 
 #include "bmesh_py_types.h"
 #include "bmesh_py_types_select.h"
+#include "bmesh_py_types_customdata.h"
+
 #include "bmesh_py_utils.h"
 
 #include "BLI_utildefines.h"
@@ -129,7 +131,8 @@ PyObject *BPyInit_bmesh(void)
 	PyObject *sys_modules = PySys_GetObject("modules"); /* not pretty */
 
 	BPy_BM_init_types();
-	BPy_BM_init_select_types();
+	BPy_BM_init_types_select();
+	BPy_BM_init_types_customdata();
 
 	mod = PyModule_Create(&BPy_BM_module_def);