Rather than use the P4-M mobile cpu in notebooks, it seems like most manufacturers are now including notebooks based on the desktop P4 cpu.
I recently noticed this while doing some research, and found that notebooks from MicroExpress, Sager Notebooks and Alienware are all selling notebooks (from the Taiwan based manufacturer, Clevo) based on desktop P4s.
Desktop P4s are cheaper than P4-M chips, and are faster (more L1 cache?).
ZDNet has an article here about Dell’s upcoming Inspiron 5100 released in Europe (and soon in the US) which is also based on the desktop P4, and mentions other manufacturers also following this trend: Gateway, HP, Toshiba and Sony, all either have or will have desktop P4 based notebooks on the market.