df-from-product.py

import itertools
import pandas as pd

values = [('A', 'B', 'C'),
          ('1', '2', '3'),
          ('P', 'Q', 'R')]

df = pd.DataFrame([''.join(p) for p in itertools.product(*values)])

"""
      0
0   A1P
1   A1Q
2   A1R
3   A2P
4   A2Q
5   A2R
6   A3P
7   A3Q
8   A3R
9   B1P
10  B1Q
11  B1R
12  B2P
13  B2Q
14  B2R
15  B3P
16  B3Q
17  B3R
18  C1P
19  C1Q
20  C1R
21  C2P
22  C2Q
23  C2R
24  C3P
25  C3Q
26  C3R
"""

there is a little typo up there where lists is used instead of values...
df = pd.DataFrame([''.join(p) for p in itertools.product(*values)])

@danmaps I knew I should've written tests! Fixed now, thanks for the catch.