I'll gladly check it, but you have no way to know that I'm not taking your private keys and absconding with the loot. An open-source tool or hand-checking is probably your best bet.
And where to find such a tool?
hand checking will take me weeks
also i would need to install many different versions of qt ..
To get you started, you will need something like e.g.
Pywallet,
some scripting language (I'd do it in Perl),
put all wallet.dat files into one directory,
have the script open the files,
export private keys into a text file (with Pywallet),
import the private keys into one new wallet.
Easy. If your wallets are encrypted, it'll be more trouble, though.