ok, I was possibly overthinking
Instead you can set a minimum width of the container.
Edit skin/reboot/custom/reboot_head.tpl
Before...
Code:
</style>
{/literal}
Insert...
Code:
.container { min-width: 1400px; max-width: 1400px; }
But you may also have to remove the media queries at the bottom of skin/reboot/css/reboot.css (they control the responsiveness).