Tick Performance is offering to build a master cylinder kit for trucks equipped with a manual transmission. This kit should help you powershift since it cures the master cylinder and can be adjusted unlike the crappy stock cylinder which is the main factor that holds you back.
If you are anywhere near Mooresville, NC and have a stick shift truck, i will be willing to pay you just to go to Tick Performance and have them take out the measurements of your truck's master cylinder so they can build one perfectly.