Is it possible to setup 2 Plesk servers with the same data so that one is acted as a backup server for failover scenario? It's called redundancy or multi-hosting.
This functionality is not supported in Plesk at the moment. You may want to vote on implementation of this functionality in Plesk on Plesk User Voice portal.
The top-ranked suggestions are likely to be included in the next versions of Plesk. You can get the information about the updates in our products in the following public sources:
https://partners.plesk.com/ - public roadmaps for partners;
http://kb.plesk.com/subscriptions/index.html - knowledge base, each product update comes with corresponding KB article;
http://kb.plesk.com/rss/?p=PLESK - RSS feeds