I posted the approach I used a few months ago- selectively imported photos from multiple iPhoto libraries to various folders within Lightroom.
The way I did it:
1. Create a symbolic link at the operating system level to your iPhoto library.
Assuming your iPhoto library exists in its default location (~/Pictures/iPhoto Library for example):
open the Terminal app (Applications Utilities Terminal)
create a link to an existing iPhoto library by entering a command along the lines of:
ln -s ~/Pictures/iPhoto\ Library ~/Pictures/iPhoto_import
note: you can press the tab key (after typing only a few characters iPho) to correctly complete the directory name iPhoto Library in the command above
2. Once this link is created at the operating system level, you can use the standard Lightroom import mechanism to selectively copy/import portions of your iPhoto library into various Lightroom folders (or however you choose to organize them).
Note: make sure you select the Masters subfolder within the iPhoto folder as the import source or else you will import thumbnail and intermediate dupes (in the graphic below, I created test_iPhotoLibrary symlink so you could see what I'm talking about).