snapshot of the game's Trophy screen shows a Platinum Trophy for the game -- one that's reserved for full retail games. Shorter, cheaper games on PSN, such as PixelJunk Eden, Super Stardust HD and PAIN, do not feature a Platinum Medal. However, full-priced retail games, such as Uncharted, do grant Platinum Trophies.
With this evidence, we can postulate that WipEout HD will be available for download for at least $30 (the cost of Warhawk, downloaded from the PLAYSTATION Store). SCEA still hasn't announced an official release date or price for the game, but rest assured that the news is forthcoming.