577 votesRick Sportel commented
I would also love to use a plugin like this but I'm not going to invest money in a plugin that is not even there yet.
For a customer I managed to modify the standard product page by hooking a function that displays a direct quote form below the product description.
Click this link to see it working:
On this page click the grey button just below the product title and price and you will be directed to the form below the product.
Works fine actually. High conversion as visitors can request a quote directly from the product page keeping them away from an annoying checkout process.