I have a Runva 17,500 lbs (8 tonne) winch on my FG84 Canter. Unless you are going to go hydraulic, I think that this is the biggest electric winch you will be able to get.
The problem is that the market for winches is heavily weighted towards "normal sized" 4x4 vehicles, meaning that not a lot of companies make a winch model larger than 12,000 lbs.
My personal opinion is that the Chinese winches are not all that bad, but they are cheaper for a reason. As an example... threaded holes for the motor mount are normally just tapped into the cast iron.
That's fine if you never plan on servicing the winch, but if you do, it is likely you will strip those threads pretty easily. I would also question the quality of the grease that is supplied with Chinese winches.
If, like me, you would like to ensure that your winch will work when you need it to, some simple modifications will increase it's reliability. Two things that I did was to put stainless steel helicoils in all of the tapped holes and I replaced the grease with a good quality high pressure/waterproof lithium based grease.
I would also strongly recommend using synthetic rope, opposed to cable.
There are arguments for using either, but using synthetic rope is normally safer it will reduce the overall weight of a 17,500 lbs winch significantly (we're talking well over 20Kg for a 30m rope).