This is a great effort and shows that the RISC OS GUI is usable on this device format.
HP are using the Samsung S3C2400 series ARM processors in the new iPAQ's. This is the same integrated ARM9 processor used in the A9home. Perhaps RISC OS Adjust has the advantage over RISC OS 5 as a possible PDA OS. The highly integrated nature of this processor means that it may be possible to port RISC OS without having to write new video drivers, quite a big job if you were to port RISC OS 5.
The performance of a native OS rather than an emulated one on a PDA would make your eyes water.
Also of interest to some readers is that some of these devices will run at 500MHz