You have a slight misunderstanding of how clustering works.

In a clustered environment, there are SQL instances and host nodes.  The two
entities are entirely independent.  An Instance can run on one or more
nodes.  A node can host zero or more instances at any given time.
Generally, I set up clusters with each instance on a preferred node, just so
I can find it easily.  So, what you are looking for is a cluster with three
nodes and three SQL instances, each instance normally running on a separate
node.  In addition, the instances may be different editions of the SQL
Server product.

Since instances are independent of each other as well as the host nodes, you
can mix and match versions and editions on the same cluster, just like on a
stand-alone system.

Hi

Just to add to Geoff's comments.

Since you have 3 nodes, Standard Edition will not install on all 3 as it
supports 2 node clusters only.

So you have to pick the possible owner nodes very carefully.

Regards
--------------------------------
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland

IM: mike@epprecht.net

MVP Program: http://www.microsoft.com/mvp

Blog: http://www.msmvps.com/epprecht/