I would be nice to be able to pass a parameter to pppd, to make it call it's interface something different than pppX (and still use pppX when it's not passed). The reason I'm asking for this is, that I use PPPoE for my internet connection, and use PPP for my VPN connections. The problem is, that I use ppp+ to catch all my vpn connection in my firewall script, and now, after I changed ISP and have to use PPPoE, it breaks, since it also catches ppp0, which isn't a VPN connection, but my PPPoE connection. I have been talking with the baselayout guys, and they will implement the baselayout stuff, if pppd gets this feature. I don't want to rename every ppp connection, just a single one, and let the rest still use pppX as thier name.
Unfortunately this cannot be done. The PPP kernel support create network interfaces named as "ppp${unit}", where unit must uniquely identify the PPP link. User-space tools also expect PPP interfaces to be named accordingly (e.g. pppstats). If someone will ever make Linux PPP interface names user-selectable, he/she will need to rewrite the entire kernel and user space PPP support from scratch.