Answer:
Current Intel Pentium 4-supporting series roadmap:
IC7-G: i875P MCH; ICH5R; 400/533/800MHz QPB; 4 DIMM slots for up to 4GB of PC2100/PC2700 or PC3200 (DDR400) memory; dual-channel memory bus support: memory modules used should be identical and installed in pairs; AGP 8x, 5 PCI slots; 2-channel ATA-33/66/100; 2-channel Serial ATA-150 controller (ICH5R) with RAID 0 support; Silicon Image Serial ATA-150 RAID controller with RAID 0,1 support; 10/100/1000Mb/s Ethernet controller; 6-channel AC'97 sound; USB 2.0; FireWire (IEEE-1394) controller; ATX. Mass production to start in the first quarter this year.
IS7-G: i865PE MCH; ICH5; 400/533/800MHz QPB; 4 DIMM slots for up to 4GB of PC2100/PC2700 or PC3200 (DDR400) memory; dual-channel memory bus support: memory modules used should be identical and installed in pairs; Gigabit Ethernet. Mass production to start in the first quarter this year.
IS7-C: i865PE MCH; ICH5; 400/533/800MHz QPB; 4 DIMM slots for up to 4GB of PC2100/PC2700 or PC3200 (DDR400) memory; dual-channel memory bus support: memory modules used should be identical and installed in pairs; Serial ATA-150. Mass production to start in the first quarter this year.
IS7-M: i865G MCH; ICH5R; 400/533/800MHz QPB; 4 DIMM slots for up to 4GB of PC2100/PC2700 or PC3200 (DDR400) memory; dual-channel memory bus support: memory modules used should be identical and installed in pairs; Intel Extreme Graphics 2 integrated core; AGP 8x, 5 PCI slots; 2-channel ATA-33/66/100; 2-channel Serial ATA-150 controller (ICH5R) with RAID 0 support; 10/100Mb/s Ethernet controller; 6-channel AC'97 sound; USB 2.0; ATX. Mass production to start in the first quarter this year.
IS7-E: i865P MCH; ICH5; 400/533MHz QPB; 4 DIMM slots for up to 4GB of PC2100/PC2700 or PC3200 (DDR400) memory; dual-channel memory bus support: memory modules used should be identical and installed in pairs (note that officially Intel does not support dual-channel PC3200 with i865P); AGP 8x, 5 PCI slots; 2-channel ATA-33/66/100; Silicon Image Serial ATA-150 RAID controller with RAID 0,1 support; 10/100Mb/s Ethernet controller; 6-channel AC'97 sound; USB 2.0; FireWire (IEEE-1394) controller; Mass production to start in the first quarter this year.
SI7: SiS R658 North Bridge and SiS693 I/O controller; 400/533MHz QPB; 2 RIMM slots for up to 1GB (not a lot, isnt’t it?) of PC800, PC1066 or PC1200 RDRAM memory; dual-channel memory bus support: memory modules used should be identical and installed in pairs; AGP 8x, 5 PCI slots; 2-channel ATA-33/66/100/133; 2-channel Serial ATA-150 controller with RAID support; 10/100/1000Mb/s Ethernet controller (for SI7-G; SI-7 features only 10/100Mbit/s Ethernet); 6-channel AC'97 sound; USB 2.0; FireWire (IEEE-1394) controller; ATX. In production. More information in this news-story.
BH7: i845PE; ICH4; 400/533MHz QPB officially, up to 800MHz when overclocked; 3 DIMM slots for up to 3GB of PC2100, PC2700 or even PC3200 (DDR400) DDR SDRAM memory; AGP 4x, 5 PCI slots; 2-channel ATA-33/66/100; 2-channel Serial ATA-150 controller for 1 device; 10/100Mbit/s Ethernet controller; 6-channel AC'97 sound; USB 2.0; ATX. In production. More information in this news-story.