I'm considering modifying a Ford Ranger WildTrak pickup truck with a chassis mounted small crane for lifting heavy items in and out of the bed. For example: big rocks or large cement planters. I'd also like to mount a 12v winch in the bed of the truck and attach it to the chassis.

Can anyone recommend a reliable place in the BKK area that could install / sell / fabricate these kinds of things properly?

Here's a link to an example image of a pickup crane with a hand crank winch...

https://lh4.googleusercontent.com/proxy/aO36nMj9bDvMxPZPOs_Qf86zkHPQXYwjnBra3s9fXKYbZ2YIs-2rZDfZyiYl68wi5fJc3HCgfNbC69vaEWhCdoXIl47nG-pgsiyUpRTcr1N213mA-VweCDoASYjgy6tCZATvw0NiEyytdWd_eLAXEe2_dx7DX4nL=w384-h384-nc

I'd also like to mount a winch in the bed of the truck... Either as in image below or somehow tied into the chassis...

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQe1nwol9g1fDd06ximkjVmDvZ8ZJ_0sSgX4rOAEsvl7C4DYgPj9A

As far as the winch in the bed, it would be a lot more economical to use the standard front mount and run the cable under the truck for use at the back of the truck.

As far as the winch in the bed, it would be a lot more economical to use the standard front mount and run the cable under the truck for use at the back of the truck.

I understand what you are saying, but I am hoping to winch things into the bed of the truck.

You may find that once you have the crane you don't need the winch. You could use a winch block to pull things into the bed with crane's cable or if the crane is mounted at the back of the bed, slew stuff in.