Let It Wave, a european image processing company, claims their bandlet (or bandelet depending which page of the site you read) technology allows them to upconvert SD sources to HDTV resolutions with no flickering or artifacts whatsoever. We won't try to decipher the mathematic reasons they give as to why this is possible, but you can check out their tech page for yourself.

Their press release includes an endorsement by the namesake of the Faroudja DCDi upconverter, now all we need to do is see some products and maybe watching standard definition won't hurt so bad anymore.