How can I remove the RAW image files from my iPhoto Library?
No there isn't. Pretty much the point of iPhoto is that it treats the original file as a "digital negative" and the non-destructive editing feature is based on that. So, iPhoto (and Aperture) never perform any operations on the Original, only on a copy.

It doesn't make multiple versions, tho. There's only one edited version.

What you can do: Export the Edited Versions. Delete the photos from iPhoto. Re-import the edited versions. You'll lose a lot - not least the ability to edit non-destructively - but if that's what you want.

A better solution is to use an app that does what you want - that is, edit the pics directly.

You know that you can store an entire iPhoto Library on a disk formatted Mac OS Extended (Journaled)?