If you have/are using an Exchange or IMAP account for your e-mail, you can access both Drafts and Sent e-mails. You'll need to navigate to the main e-mail account to see these, however, you can't see them in the All Accounts view portion of the Mail app.
Take a look at the pictures in this thread (the 4th post): Extra folder in Mail account. It shows how you can get to the main accounts to access the Drafts and Sent folders.
If you are using a POP mail account, then no, you won't have access to these folders on the iPad. Just the way POP mail is designed and works on the iPad...
Hope this helps.