However, you could use the python api to do this, and execute a python script in blender from the command line. (see this question)

Note that it loops through each scene to set these properties globally. (see this)
You can run this from the command line with

Note that to set the viewport border you must use this instead, but you most likely are interested in camera border as viewport border is only relevant for using the realtime rendering feature. (see this post for more info)

You could also combine different Cycles renders by using the Seed value. (See this post for more info)

This also is a good way to remove fireflies.

However, you could use the python api to do this, and execute a python script in blender from the command line. (see this question)

Note that it loops through each scene to set these properties globally. (see this)
You can run this from the command line with

Note that to set the viewport border you must use this instead, but you most likely are interested in camera border as viewport border is only relevant for using the realtime rendering feature. (see this post for more info)

You could also combine different Cycles renders by using the Seed value. (See this post for more info)

This also is a good way to remove fireflies.

Note that to set the viewport border you must use this instead, but you most likely are interested in camera border as viewport border is only relevant for using the realtime rendering feature. (see this post for more info)

This does not answer your question about tiles, but as you mentioned you want this for rendering on multiple machines, I thought I would add this.

You could also combine Cycles renders with the Seed value. (See this post for more info)

So to render half of the image vertically, you could run this:

import bpy

for scene in bpy.data.scenes:

    scene.render.use_border = True
    scene.render.use_crop_to_border = True
    #this sets the render border to the left half of the camera. 
    #to render the right half, set max_x to 1 and min_x to .5
    scene.render.border_max_x = .5
    scene.render.border_min_x = 0
    scene.render.border_min_y = 0
    scene.render.border_max_y = 1
    scene.render.tile_x = 32
    scene.render.tile_y = 32
#then render:
bpy.ops.render.render()

Note that to set the viewport border you must use this instead, but you most likely are interested in camera border as viewport border is only relevant for using the realtime rendering feature. (see this post for more info)

This does not answer your question about tiles, but as you mentioned you want to do this for rendering on multiple machines, I thought I would mention this.

You could also combine different Cycles renders by using the Seed value. (See this post for more info)

Because of this, you might be better off using the Render Border; this will allow you to exactly define what section of the image to render.

The border region is defined with four values between 0 and 1 where 0 is the left or bottom edge of the camera, and 1 is the right or top edge.

Note that to set the viewport border you must use this instead, but you most likely are interested in camera border as viewport border is only relevant for using the realtime rendering feature. (see this post for more info)

Because of this, you might be better off using the Render Border; this will allow you to exactly define what section of the image to render.
You could then call blender to render repeatedly, using a script to pass different render border dimensions to do your own "tile render".

The border region is defined by four values between 0 and 1 corresponding to the locations of the four sides of the render border relative to the camera where 0 is the left or bottom edge of the camera, and 1 is the right or top edge.

Note that to set the viewport border you must use this instead, but you most likely are interested in camera border as viewport border is only relevant for using the realtime rendering feature. (see this post for more info)

Seeds:

This does not answer your question about tiles, but as you mentioned you want this for rendering on multiple machines, I thought I would add this.

You could also combine Cycles renders with the Seed value. (See this post for more info)

This also is a good way to remove fireflies.