guessing time:

1. they intend to do a double release of Wipeout Pulse PS2 and Wipeout HD - DLC at the same time (i'm sure if studio liverpool had a say in release dates and marketing they'd love this!)

2. sony dicking around, unsure about releasing it/and/or when

3. adding features

4. problems with game

5. game not coming out.

Pick one, i like Number 1 personally. Would be ok with number 3, if done right. but suspect number 2 is guilty.