I believe the ProCurve 2510s are stackable, so in theory, one can create a LACP VIF with members across the two switches. Having said that, the specifics in the diagram you laid out begs a few questions/clarifications
a) On the FAS2020, multi vif01 (lacp) is indicated. In NetApp world, a vif type is either multi or lacp - not both. Type "multi" is a static EtherChannel (active/passive connection and no switch configuration is necessary) and type "lacp" is a LACP VIF (where it creates active/active connections and switch configuration IS necessary). You'll need to pick one
How's the Procurve 2510's working out for NFS access to the storage. I'm planning to purchase 2 of these on ebay for a home test network and just wanted to know if you ran into any issues with them. Thanks.