Not really. Only other options are a GPU (Global Premier Upgrade - given to Premier 1K members), or an online "buy-up" offer. Log into your reservation and see if there's an upgrade option and what the price is. Also, this option may come way down in price within 24 hours of departure, so be sure to check again at that time. There really isn't a way to spend extra miles to upgrade in lieu of the co-pay for the regular upgrade that you already found.