Something like this:

import gzip
fin = open("/dev/urandom", "rb")
fout = gzip.GzipFile("out", "wb")
for i in range(4500): fout.write(fin.read(1024*1024))
fout.close()

will result in an error like:

Exception 'long int too large to convert to int' raised
of class 'exceptions.OverflowError':
...
  File "/usr/local/lib/python2.2/gzip.py", line 253, in
close
    write32(self.fileobj, self.size)
  File "/usr/local/lib/python2.2/gzip.py", line 19, in
write32
    output.write(struct.pack("<l", value))

Tested in python 2.2.1