Dudadiesel makes the plate chillers that many others sell unbranded (or their brand). Like kegcowboy,AHS,etc. Duda has been very helpful in conversation, but they are really a 'supplier' and not a home brew shop. Ask them questions about how many minutes for flow rates and such, but I'd not bother asking a ton of brewing specific inquiries. They are really a biodiesel gear company (not that there's much difference).
I think that their prices are quite good. My 30 plate small is great with the back mounting studs.