WinShell is a free multilingual integrated development environment (IDE) for LaTeX and TeX. The program includes a text editor, syntax highlighting, project management, spell checking, a table wizard, BibTeX support, Unicode support, different toolbars and user configuration options.
WinShell, which is already portable, can be combined with portable LaTeX
so, a complete portable LaTeX environment could be provided.
The link to WinShell: www.winshell.org