Ubercart

You can disable any checkout panes you wish:

/admin/store/settings/checkout/edit/panes

Just make sure your customers are aware that you can only ship to billing addresses and I think you'll be fine.

So you want "My billing information is the same as my delivery information." to be checked by default?
And address copied over without making user click on that evil check box? Try this hack.

Edit uc_cart_checkout_pane.inc

function uc_checkout_pane_delivery($op, &$arg1, $arg2) {

...
          '#attributes' => array('onclick' => "uc_cart_copy_address(this.checked, 'billing', 'delivery');",
				 'checked' => "yes"),
        );

and

 
function uc_checkout_pane_billing($op, &$arg1, $arg2) {

...
          '#attributes' => array('onclick' => "uc_cart_copy_address(this.checked, 'delivery', 'billing');",
				 'checked' => "yes"),
        );

Its all nice and pretty now but what will take care of copying that address from the delivery to billing?
In case you haven't noticed the point of clicking the check box is just that - call uc_cart_copy_address()
which takes care of copying. Lets see if we can hijack another click here. Inside the script.js add

$(document).ready(function() {
	$("#edit-continue").click(function(){
			if ($('#edit-panes-billing-copy-address').is(':checked')){
				uc_cart_copy_address(true, 'delivery', 'billing');
			}
			if ($('#edit-panes-delivery-copy-address').is(':checked')){ 
				uc_cart_copy_address(true, 'billing', 'delivery');
			}
	});
});

What just happened!? We told the "Review Order" button to copy the address before submitting the form.
That's it. At least for that part. Now lets finish the job and make it all pretty. Since we're saying
our address is the same there's no point to display the empty form underneath confusing the customer

Back to script.js right underneath the closing tag for $(document).ready(); Insert the following code

$(window).bind('load', function () {
	if ($('#edit-panes-billing-copy-address').is(':checked')){
		$('#billing-pane div.address-pane-table').slideUp();
	}
	if ($('#edit-panes-delivery-copy-address').is(':checked')){
		$('#delivery-pane div.address-pane-table').slideUp();
	}
});

And if you haven't figured it out on your own, It'll close the second pane (billing/delivery - depends on
the type of check box you have).

Why not just do this:
Create a custom module for your site. include the following line in your module_name_form_alter(&$form, $form_state, $form_id)

then create a billing.trigger.js inside your custom module containing the code below:

The Checkout Tweaks module seems to have solved this issue.

http://drupal.org/project/uc_checkout_tweaks