Hi,
Having an export of all the orders with a specific value in a custom order field, that's possible with the mass action system (menu System>Mass actions).
There, you can use the "order column" filter on your custom order field's column name to filter only the orders with the value you want, and you can use a "export CSV file" action to get the CSV with the columns you want once you click on the "process" button.
Now to have a summary of the quantities per product, that's possible with a report with the display mode "listing", on the type "products". But you can't filter based on a custom field, only by date, categories, payment method, shipping method, and order status.
And to have both in one export is even less possible. If that's really what you want, I can only think about developping a custom export script as a plugin to get that.