If by standard Clustered ONTAP pair you mean a single HA Pair, maximum distance is determined by maximum HA Interconnect length (10GE or Q-SAS or <30m Infiniband) and maximum length of cabling from controller to disk shelves (SAS - 5m, FC - 500m).
So for modern HA pairs you're looking at a distance of about 5m between the 2 nodes. (Atto Bridges might extend that...)
Distance of pairs within a clustered ONTAP cluster would be determined by the maximum distance of the 10GE connections from the node(s) to the Cluster Interconnect Switches... Something like : HA Pair <- ~300m -> Switch <- ~300m -> HA Pair
Hope that helps