I concur with Ian. With the current state of the PEAR Group and a non-existant QA department who's going to manage adding PEAR to all of the packages?
We should let PEAR for PHP4 die a slow death and worry about this sort of stuff with regards to a PEAR for PHP5. That or wait for namespaces.
I, as well, don't plan on putting PEAR in front of any of my packages (at least until PHP releases a 'Net_Curl' class or a 'Payment_Process' class).