I recently installed and tested the USBTex portable Latex environment and I have to say it's really great (http://goo.gl/7pd5). The only thing that's lacking for this to be able to appear inside the PortableApps 'Launcher' is an '.exe' file than can bundle three '.bat' files together.
Right now to launch the tex editor of USBTex you have to follow three steps:
1.- Run 'demarrer.bat
2.- When the above is finished (although I think it's not mandatory to wait until it's finished), run 'texmaker.bat'
3.- After you are done using the editor, run 'arreter.bat'
So basically all that's needed is an '.exe' file that can: run the first '.bat' file; wait until this one is finished and then run the second file (which opens the editor) and finally wait in the background until the editor is unloaded and then run the last '.bat' file.
I'm afraid I don't have the knowledge to script this to work under a Windows environment, but I think this shouldn't be too difficult for someone with some skills with VB or something like that.
Anyone up for the task??