Convert dictionary of lists of tuples to list of lists/tuples in python
Have a look at pandas:

import pandas as pd

d = {
            'p2': [(1355150022, 3.82), (1355150088, 4.24), (1355150154, 3.94), (1355150216, 3.87), (1355150287, 6.66)],
            'p1': [(1355150040, 7.9), (1355150110, 8.03), (1355150172, 8.41), (1355150234, 7.77)],
            'p3': [(1355150021, 1.82), (1355150082, 2.24), (1355150153, 3.33), (1355150217, 7.77), (1355150286, 6.66)],
} 

ret = pd.DataFrame({k:pd.Series({a-a%60:b for a,b in v}) for k,v in d.iteritems()})


returns

              p1    p2    p3
1355149980   NaN  3.82  1.82
1355150040  7.90  4.24  2.24
1355150100  8.03  3.94  3.33
1355150160  8.41  3.87  7.77
1355150220  7.77   NaN   NaN
1355150280   NaN  6.66  6.66


It is not a list of lists, but using pandas you can do much more with this data (such as convert the unix timestamps to datetime objects with a single command).