Today I needed to extract an MSI manually and since the LessMSI gui doesn't support drag n'drop I decided to quickly fix that and add that feature to the LessMSI GUI :)
You can run this improved version of LessMSI from O2 or by downloading the 4.8Mb stand-alone file from Util - view and extract MSI files (using LessMSI) v1.0.exe , which when executed looks like this (after dropping an MSI in the DataGridView):
Note that this version also has a REPL menu, which you can use to script the LessGUI (and the data it holds)
Here is the code that creates the GUI and the stand-alone exe package: