you can do the same thing with python  built-in function "hash".

The qHash functions is a template because of that this is not exported in
PySide bindings.

[Not an expert on this topic]
The hash of Qt is different from the hash function used in python for strings.
At least doing "hash (someString)" doesn't return the same results as in C++ . 

As a work around, I translated the Qt hash function for strings into python. 
#
# Python translation of :
#
https://qt.gitorious.org/qt/qt/blobs/d12681a4cf1227d0e92fc7cf12aa3977e6ffe3fe/src/corelib/tools/qhash.cpp#line76
#
def qhash (inputstr):

    instr = ""
    if isinstance (inputstr, str):
        instr = inputstr 
    elif isinstance (inputstr, unicode):
        instr = inputstr.encode ("utf8")
    else:
        return -1

    h = 0x00000000
    for i in range (0, len (instr)):
        h = (h << 4) + ord(instr[i])
        h ^= (h & 0xf0000000) >> 23
        h &= 0x0fffffff

    return h

yes the qhash and python hash funcation, is not the same algorithm but they
have the same propose. 

this is the hash function used on string objects:

class string:
    def __hash__(self):
        if not self:
            return 0 # empty
        value = ord(self[0]) << 7
        for char in self:
            value = c_mul(1000003, value) ^ ord(char)
        value = value ^ len(self)
        if value == -1:
            value = -2
        return value

Why you do not want to use the python version there is some problem with that?
you can use either the python hashlib functions, check:
http://docs.python.org/library/hashlib.html

The music player in Harmattan is saving the album art in
~/blablabla/qHash(album + artist).png and my code must read the image in that
exact same location. 

Actually, the use-case is very specific and nobody should use qHash for
anything "external" to the application like a file name. I guess we can close
this as INVALID or WONTFIX. Sorry for the noise.

ok then, I will mark as INVALID since you agree with that.

Release PySide 1.0.6