Guess what? I finally heard from someone at Blogger. Here is the reply they gave. Not very successful in terms of finding my lost template but at least the things are clearer.
Wish they would tell us these things earlier, so that we can take precautions!
If anyone out there is using Blogger and you change their template, I suggest you do as I plan to do. Save a regular copy of your template.
Grrrrr.
Here is the email I received:
"I'm afraid you've fallen victim to a bug in our system which occasionallyloses template data. Your posts are still safe, but unfortunately we werenot able to recover your template for you. To use one of our defaulttemplates, you can click the Pick New link on the Template tab. This willlet you publish your blog again while you recreate your old template. Weapologize for the inconvenience and we are working on getting this problemfixed. However, it is always a good idea to save your own copy of atemplate if you make extensive customizations.
Sincerely,
Steve
Blogger Support Team"
Please keep my name Anonomous