I made an extra option in the uc_addresses admin to not allow editing the delivery and billing address fields in checkout. Only the available addresses from the My Account pages can then be chosen.
If that option is active all delivery and billing fields are set to readonly. They are still shown, because if you would omit the panels, the addresses are also not shown on the order review and the invoices. I chose for "readonly" and not "disable", because disabled field values are not posted.
Because readonly is not a valid tag for "select" fields I used the readonly jquery plugin for that.
For now I added the jquery.js en .css in the uc_addresses module dir.
If you think this is a good feature I'll gladly make a more appropriate solution for the jquery files. (There are quite a few in drupal world, have not decided which I prefer)
Place the .js and .css file in the uc_addresses dir and use the patch file in the /sites/all/modules dir.
(This patch is related to http://drupal.org/node/498738. With both you can get more control over the addresses used by the store customers)