Is there any way to minimize str()/unicode() objects memory usage [Python 2.6.4] ?

[dmtr]

I'm running into some performance / memory bottlenecks on large lists.
Is there any easy way to minimize/optimize memory usage?

Simple str() and unicode objects() [Python 2.6.4/Linux/x86]:
>>> sys.getsizeof('')      24 bytes
>>> sys.getsizeof('0')    25 bytes
>>> sys.getsizeof(u'')    28 bytes
>>> sys.getsizeof(u'0')  32 bytes

Lists of str() and unicode() objects (see ref. code below):
>>> [str(i) for i in xrange(0, 10000000)]   370 Mb (37 bytes/item)
>>> [unicode(i) for i in xrange(0, 10000000)]   613 Mb (63 bytes/item)

Well...  63 bytes per item for very short unicode strings... Is there
any way to do better than that? Perhaps some compact unicode objects?

-- Regards, Dmitry

----
import os, time, re
start = time.time()
l = [unicode(i) for i in xrange(0, 10000000)]
dt = time.time() - start
vm = re.findall("(VmPeak.*|VmSize.*)", open('/proc/%d/status' %
os.getpid()).read())
print "%d keys, %s, %f seconds, %f keys per second" % (len(l), vm, dt,
len(l) / dt)