Has anyone dealt with large volume serialized items? We deal with serialized items on SO’s and PO’s in the thousands and using the native Item Receipt and Item Fulfillment express entry is just not feasible. We’ve tried the CSV imports but it’s inconsistent and too challenging for our warehouse staff to use.

You may want to consider an intermediate application that creates the user experience you want then talks to Netsuite via a restlet. I might build a node/react application with a dedicated database, and then employee a lambda function to process the data. You'll want to be considerate of your design so as to think about what else could come down the pipe, but tis would be a worthy effort that would likely provide significant return on time spent. Example, what if you wanted to consume Serial Numbers via edi, how will your system deal with conflicts.