Different checkout path for International customers needing a shipping quote

With 200+ countries and 1000+ different sized products that can be ordered in any combination, it's impossible to provide an in-flow quote on international shipping, therefore we need a way of capturing a customer's cart and details without them getting payment options - they need to stop and be quoted.

We have set up 'get a quote' as delivery option but as it has to have a value, dozy customers just pay it - whether we set it at £0 or £1000, causing a huge headache for all.