One local dealer told me that HD DVD players can easily be upgraded to 1440P. And that may be their ace in the hole, with 1440P already being discussed as the next gen HDTV's. Blu-ray do not have that capability. They would have to basically redesign their players.
There's nothing magical about HD DVD when it comes to supporting 1440p. If firmware updating could allow them to support a new HD spec, chances are that BD could do the same as well. BD would actually be better suited because the higher bit-rates would do better for these increased-resolution signals.
Comments from any "dealer" about the inner workings of HD DVD or BD products is specious at best. The reality is that hardware on both sides uses chip-based decoders which are probably the limiting factor in whether or not existing devices could be flash-updated for new specs or not.
Regardless, there's no "ace in the hole" having anything to do with 1440p on either side.