A question for Blogger experts

A question for the hive mind:

When I created this blog, I created a Google Account at the same time, with the blog associated with it. The Google Account is defined with my old email address. How do I get it moved to a new email address?

The main reason I want it changed is because I want the notification emails (sent by Blogger whenever anyone posts a comment here) to come direct to my new address, rather than my old one.

At first sight, this seems simple: the "My Account" link on the Blogger home page opens a page which in turn has a "Change email" link on it. Alas, if I type in my intended new email address, an error message is shown:

• A user with the email you specified already exists

In a way, this is no surprise, since that new address is being provided by Google Apps. So I've already got two different Google Accounts - one attached to this blog, and the other attached to my new email address. Ideally, I'd like to merge these two accounts, but I doubt this is possible...?

That takes me to plan B: keep the blog associated with the same account as before, but alter this account so that notification emails are sent to a different email address. But at the moment, I don't seem to be able to do that either.

Does anyone have any bright ideas?