I only did one like this – all created out of stock video and animated stills. All rotated in a 16×9 Premiere project – so that when looking on the computer screen it was sideways – but when played out (real time) to a real vertically mounted monitor (only a small one mind you) it looked ok. None of the 4×3 source elements were used full screen – titles and other graphics elemenst filled the bottom or top. In fact, most elements were used in a PIP fashion. Looked good when seen from the intended distance.
I would guess that if you shoot footage in SD, you make sure that you can cut off as much as is required from each side.