Hi k.leeser,
Unfortunately the LeadStatus table cannot be altered as Method automatically inserts these values when converting the lead to a customer. The LeadRating can be altered, however you'll need to create a simple screen to edit and add values. This screen is really simple and just needs to include a grid to see the values, the LeadRating text field for editing or entering a new value, and a button to save the record and refresh the grid.
If you don't mind me asking...why do you want to add additional Lead Statuses?
- Adam