Yeah, I didn't prepare a packet per se but I have done something some what similar. Since it's summer, I emailed the people I thought could write a good LOR for me and who I knew on a personal level asking them if you would write a LOR for me but also giving them ample opportunity to decline (ie I understand you are very busy so if you do not have the time or for any reason whatsoever would prefer not to write a recommendation for me, I completely understand, etc).
My first prof emailed back right away asking for specifics to include (ie the grade I achieved in her class, the topic of my paper, and what I got in another (much larger) class that she also taught in since she was out of the country and didn't have access to her files) and asking if there was anything I would like her to cover. I needed some time (prob. should have done this before but it's a learning process) about what I wanted each letter to add to my profile, and so I emailed her back giving her the info, and giving her an idea of what I'd like her to focus on, as well as what has interested me about law (and particularly how it was similar to the class she taught). This profi I know the most well, since the main class of her's that I was in was a full year class comprised of about 10 people.
The second prof emailed me back saying he would be more than happy to write a letter for me and asked when would be a good time to meet up and to bring anything else I was sending in with my application to make sure it all gelled.
The third prof emailed me and said he'd be more than happy to do a LOR, just tell him what to include. He's fairly new to being a prof I think (just got his doctorate) so when I meet up with him (or via email depending) I would probably include something like you've mentioned in terms of sample LOR's.
For all three, I felt I knew them personally (ie I could say 'hey it's 'meg' from such and such class') though if it was any time other than the summer I would have visited them during office hours and asked. When I follow up with the other two profs (the one in person, the other either in person or via email) I will give them a copy of my CV that I will be attaching, what I plan on focusing on in my applications, and perhaps what they could highlight to coincide with that.
All the prof's I've asked have been more than accomodating and very open to including a bunch of stuff and highlighting whatever I want them to. I wouldn't send them a packet right away since that seems presumptuous, but either asking them via email (over the summer) or in person, and then following that up with a packet. Like the post above, I'll also give them all a stamped envelope along with the form that needs to be attached. And once all my LOR's have been received (or sometime in Oct) I will also send them a thank-you note with a small giftcard inside. That's the plan anyway