Philips machines are already accepting dvd-r discs, as well as their dvd+r. Don't know if that's just finalised dvd-r discs though (which is a somewhat pointless claim then, as most palyers will play finalised dvd-r discs...)
However, dvd-RAM is part of the new dvd-multi format, which is what all players (except Sony & Philips) will be pushing from next year (allegedly).