http://www.proz.com/kudoz/707406
That's what I've found around here.
So I think I'll stick with clientelism, even though it may not be found in certain dictionaries, since as I saw on this question, someone posted something about an article written by a US author who has a PhD on this subject, which title had had the word clientelism in it.
btw, patronage is not the same as clientelismo, patronage is actually paternalismo, which is a different political practice. Clientelismo refers to a practice where the polititian does certain favours or gives money or objects to the people in order to get their votes. This way, they become their 'clients', and there is an exchange (money/stuff/favours for votes and support).
Patronage and paternalism are something different (check it on the dictionary, there is a subtle difference between all three of these terms)