"Awkward" Integer-indexing in MultiIndex DataFrames
As reported here: [Integer-position-based indexing of Multi-Index DataFrames](http://stackoverflow.com/questions/22361385/integer-position-based-indexing-of-multi-index-dataframes), currently, the only way to do integer-position based indexing in a Multi-Index DataFrame is: 

`df.xs(df.index.levels[N][K], level=N)`

or with:

`df.groupby(level=N).nth(K)`

where in both cases, `N` refers to the level, and `K` to the position within that level.

 I wonder why this can't be done with `iloc` since technically we are indexing the dataframe using **integer positions** on the DataFrame's `Index`.
