Need ability to un-freeze individual lines on HTML quote for repricing.

I am implementing HTML quoting for a client with a business need to freeze most of the quote lines on a given quote, but allow repricing of selected lines.  Presently, there is an Action 'Freeze Prices' available on the HTML quote header.  This sets a 'price_frozen_date' to sysdate and the pricing engine uses this price going forward to price ALL the quote lines.  However, in some scenarios, items already priced on the quote are promoted from an Open Market price list to a contract-specific price list on some date beyond the price_frozen_date.  The quote needs to have those lines re-priced