Well I've come up with a working solution to this issue on ZC 1.5.8a. I modified the products table in the database, the tpl_product_info_display.php, the collect_info.php, and the update_product.php files in order to get 'Add to Cart to View Price' functionality working. I have never published a plugin before for Zen Cart, so it may take me a bit to figure out how that all works but is anyone interested in this before I spend the time adapting the solution for the vanilla files?