Last tested: May 20, 2019
No. As far as Looker is concerned, you can only have 1 SAML IdP.
It may be possible to achieve this with IDP Federation on the authentication provider side. Basically, you give Looker a single IdP that routes to different IdPs based on the user. This article talks about it: https://www.okta.com/solutions/enterprise-federation-for-your-service/