Include non-numpy array in DataFrame
@jorisvandenbossche and I have been looking at Cythonizing some of GeoPandas.  This has resulted in us having an object that holds onto a numpy array of pointers to C-level Geometry objects.  We would maybe like to include this numpy-like object as a column in a Pandas dataframe.  However, we would still like to hold onto the object, and not have these pointers just join an integer block in the block manager.  This is useful for things like garbage collection on the C side, odd indexing rules, etc..

My intuition says that putting a numpy-like object into a Pandas dataframe without it being coerced into part of a numpy array is probably not feasible with present-day Pandas, but I thought I'd check first just in case.  We have backup plans if this isn't feasible, so it's not a big deal either way.