I know that there is a way to crosspost from WP to Blogger but I am curious if there is a way to essentially mirror WP blog on Blogger completely, in other words crosspost both posts and comments?
Your client wants to mirror on Blogger this "In case WordPress fails?!?" OMG!!!! Do they not understand how WordPress works?
Set him up a second WordPress site on a different web host or on WordPress.com! Don't put up with Blogger.
A programming solution would be to monitor RSS feeds on a psuedo-cron task and then import them with
- Import and Display RSS Feeds in WordPress
- Pseudo Cron Jobs with WordPress
- Function Reference/wp_insert_post
But whatever you do get them to stick with WordPress on the multiple sites; doing anything else is madness!