Quick Re-order aka order_history.php history beyond last order

Hello,
I've searched the forums for this and checked add-ons, without a solution. I think I may need to hack code, but would appreciate a second opinion.

I would like my Quick Re-oder box to contain a list of ALL previously ordered items, including before the last order submitted. I have experimented with this and the box will contain as long a list of items as my last order held, but the old list doesn't survive once a new order is placed. As this list could get quite long, I would want to hopefully set the max # items displayed.

My scenario is, we have a B2B relationship with another company, and they order on our site on behalf of their customers from a specialized (hidden) category. They would like their few items to always appear in the Quick re-order box.

I tried playing with /includes/templates/templates_default/sideboxes/tpl_order_history.php but I don't see anything therein that readily pertains.

Any ideas?

Thanks very much!

BEFORE you do ANYTHING ELSE, you need to upgrade to a current version of Zen Cart. Your old version contains numerous security vulnerabilities that are fixed in the latest version.
Seriously. Upgrade first.