PanelData.major_xs('A')
PanelData.minor_xs('zTwo')

import pandas as pd

ListLetter = ['A', 'B', 'C', 'D']
ListCode = [2, 1, 1, 0]
ListZone = ['zOne', 'zTwo', 'zThree', 'zFour']
ListRegion = ['USA', 'CH', 'NZ', 'CH']
index = pd.MultiIndex.from_arrays([ListLetter, ListCode], names=['letter', 'code'])
columns =  pd.MultiIndex.from_arrays([ListZone, ListRegion], names=['zone', 'region'])

PanelData = pd.Panel({'2010-01-01': pd.DataFrame(index=index, columns=columns)})
PanelData['2010-01-02'] = pd.DataFrame(index=index, columns=columns)
PanelData['2010-01-03'] = pd.DataFrame(index=index, columns=columns)
PanelData

<class 'pandas.core.panel.Panel'>
Dimensions: 3 (items) x 4 (major_axis) x 4 (minor_axis)
Items axis: 2010-01-01 to 2010-01-03
Major_axis axis: (A, 2) to (D, 0)
Minor_axis axis: (zOne, USA) to (zFour, CH)

In [67]:

PanelData.swapaxes(0,1).xs('A', 0)
Out[67]:
<class 'pandas.core.panel.Panel'>
Dimensions: 1 (items) x 3 (major_axis) x 4 (minor_axis)
Items axis: 2 to 2
Major_axis axis: 2010-01-01 to 2010-01-03
Minor_axis axis: (zOne, USA) to (zFour, CH)

In [68]:

print PanelData.swapaxes(0,1).loc[('A',2),]
zone       zOne zTwo zThree zFour
region      USA   CH     NZ    CH
2010-01-01  NaN  NaN    NaN   NaN
2010-01-02  NaN  NaN    NaN   NaN
2010-01-03  NaN  NaN    NaN   NaN

[3 rows x 4 columns]