help with creating a launcher for non-open source/freeware apps that can be run from removable media

as the subject suggests i want to create a launcher for an application that is a commercial product. now i know i cant make the commercial application its self portable, but from my understanding, i can create a batch file that starts the app and make that portable.

now i actually want to set up a program that i can use an ini file to adjust the location of the file i want to launch. an example of this would be World of Warcraft, since you can use the launcher.exe or the actual wow.exe to start the game. was also thinking of setting up a txt file for extracting reg entries into .reg files for said app(these entries would be extracted from the end users computer, since key info cant be transferred and that may be something that may come out of registry) for PA.C.

if i were to create a launching program, could i turn the program i create into a portable app. remember the program i create wont actually change any commercial application i want to use as a portable app.

grant you when/if i portable-ize said app i create i will have to deal with registry entries issues the original app sets up, but to my knowledge removing said entries from the registry isnt against any EULA, and replacing them isnt either, at least to my knowledge.

now is this a feasible idea, or am i blowing smoke up my rear end?