Show English for t() in a popup

This came up on drupal.hu so idea credit is to http://drupal.hu/tagok/aruna -- the hack described here is my idea. It'd be great if you could see the original of a translated text esp for error messages in a small JS tooltip. While locale doesn't seem to offer an alter hook or any ways to intervene, we can happily hack around and make drupal_static('locale'); an ArrayObject (i was just reviewing catch's CacheArrayObject patch a few hours ago) or more likely a three-deep structure of ArrayObjects and change the string upon return to include the original and whatever JS or CSS necessary.