I tried an iPaq (albeit not the latest with the Nevo software) and the range was appalling, about 5 ft max. Gave up on it very quickly and back in the cupboard it went. Have a look at RemoteCentral as I know Dan has done a review of the iPaq with the Nevo software.
TvRemoteController software allows you to use existing pronto CCF files which is pretty neat though. They work a treat, apart from the range