Does anyone have experience with a way for a customer to email/submit a PO and have that auto generate a sales order in our NetSuite? Looking for ways to possibly handle this besides EDI or a punchout system like Tradecentric

Look into NuOrder if that fits your situation. It's a self-service order entry portal that will allow manually entered orders via the UI or via an excel-formatted template. Another option is a Suitelet that's available without login that can be used as a UI for those customers for entering orders that will generate sales orders in NS.

Thanks Eric. I’ll look into that as we are retooling our wholesale eCommerce system