This mod is now an option in my Perk Options Mod, but will be updated in both places.

What it does:

Adds carry weight bonus to all 4 ranks of strong back, with options for how much. 

Installer will give you choice of 25 per rank, 40, and 100. There are also two scaling choices now. One adds 25, 50, 75, and then 100 for a total of 250. The other adds 40, 80, 120, 160 for a total of 400.

If you already have some of the perks:

This mod works if you already have these perks, however you will have to type two commands I have included in console to remove and re-add them.
You might need to do this even if you just have one perk.

You can see the commands in game by opening the console with ~ and typing bat strongbackhelp

You can also just use vanilla console commands.

Rationale:

Carry weight is a cool aspect of the game in my opinion, however as the game progresses gear becomes heavier and the number of items carried is larger. It also becomes less and less fun going to merchants as the game goes on. 

If you like this mod please endorse it!

Changelog:

Version 2.10
Fixed installer not working for the scaling heavy option.

Version 2.01
Fixed broken line of code in 2.0, works fine now.

Version 2.0 
Fixed installer always installing +25 version no matter what you selected.
Added two scaling options

Version 1.02
Batch files were broken, fixed. You don't need to update if you are using the regular console commands or not having to use any at all.

Version 1.0
1help file strongbackhelp had incorrect commands