A wise man recently said on this site that you cannot save face and save your ass at the same time. I can sort of understand your reluctance to pick up a white chip in your home town if you sincerely feel that there will be serious financial and professional repercussions. I just don't agree with it. What's your plan after you get the chip? Are you going to return to your hometown and participate is a recovery program? You failed to mention if you were already in a program, but since you have a sponsor then I assume that you are. And if you are, then your integrety is suspect if you don't admit to the group that you haven't been honest thus far in your recovery.
Your "other professional" friends are advising you to be thoroughly honest is all areas of your life as part of the requirement to avoid being considered an impaired professional. I think I'm just a bit confused here. You're being advised to pick up a white chip under the cloak of invisibility in a place where no on knows you. That's not being honest. After taking this first step in your new recovery plan, then you jump on the honesty wagon, do a rigorous housecleaning and all that stuff? You're building a house on a clay foundation, my friend.
You've mentioned your extensive knowledge of the subject of addiction and the fact that you hold some credentials in that area. Unfortunately, all the knowledge of addiction and all the credentials in the world aren't going to help you here. The issue isn't addiction, it's recovery. Two separate things. Trust me, as I've been in your shoes, that your knowledge and credentials are worthless. You need to learn the process of recovery, and complete and total honesty is essential here. Lurking in strange alleys to pick up a white chip so nobody finds you're not the person you had them believe you were is not complete and total honesty. I get the distinct impression that regardless of your pleas for guidance and acceptance, you're more concerned about your reputation than you are your recovery. I would suggest that your successful recovery is far more important that your professional reputation, and that such a recovery would be a great benefit to your reputation in the long run.