What about Alford pleas? I thought they existed so that you could reserve the right to appeal or avoid a civil action by avoiding an admission of guilt while acknowledging that you will likely be convicted.
IANAL but from what my lawyer friends have told me an Alford plea is practically the same as a guilty plea for purposes of appeal. In other words, it's very difficult to appeal an Alford plea. Seek legal advice before considering an Alford plea.