I have see a few shops asking for quotation set ups- The customer can see the product ( show no price)- order multiple products.
they appear in the cart - add the address , postage says payment later - all that is easy to set up -
* But when they click confirm - the item sends an invoice or email that shows the original price - (even if I tick show no price)
* For the quotation system to work correctly - all it would need is to have the email not to arrive with the price showing- I have seen a few of the good - hacker/designers get in and stop the shopping cart//or the email showing a price but I'm sure a small setup in the price area or configuration or next to catalogue would be good.