Plugin Idea: Show User Last Login Date

I have a popular site where many users register on a weekly basis, but less than half of those are actually active.

Simple plugin idea: A very small plugin that adds a new column to the "Users" page called "Last Logged in." This way i can see who hasn't logged in for more than 1 or 2 months and delete them manually.

Everyone with a popular site (or a multisite) could use this.

The following page shows this function in action, but sadly it's only raw code:

http://micahwood.me/code-snippets/wordpress-user-last-login/

Could anyone turn this into a quick plugin? That's be great!

P.S. I found a plugin today, but it's only tracking users' last login date as of the plugin's installation date. I'd like to go way back to last year...