Recommendation Letters (Ethics)

Although I am only planning to apply for Fall '09, I wanted to see if anyone could provide some insight on something that is bothering me. I am worried about my letters of recommendation and how I will go about getting them.

Positives about my situation:

1) I'm doing really well at work and a lot of people know that. I have 4 possible recommenders in mind.

Negatives about my situation:

1) My direct supervisor is on the road 90% of the time, and therefore I am not sure how well she knows me personally or my future goals/career direction. She knows that I do great work and that I bust my tail for the company, but I am just not sure what content she'd even be able to come up with for an LOR.

2) My direct supervisor does not have the best writing skills. I do not feel comfortable at all bringing this up to her, but many people in the company know that this is one of her weaknesses.

So, really what I'm wondering at this point is: Can I go ahead and write the letters of recommendation and just have her review/tweak them and sign off? I know this is completely unacceptable at a few schools - does anyone know which ones?

If I go the other route - that is, just provide her with my essays/resume and a set of bullet points and ask her to write the letters, is it acceptable for me to ask to review the LOR for grammar/spelling prior to submitting it? I do not want to offend her, but at the same time I do not want to submit sloppy LORs to M7 type schools.