Based on the latest Famitsu hardware numbers...
PSP comparisons: After 200 weeks, PSP is where PS2 was at 148.5 weeks (January 1, 2003), where DS was at 89.6 weeks (August 17, 2006), and where GBA was at 127.4 weeks (August 26, 2003).
X360 comparisons: After 148 weeks, X360 is where GCN was at 14.7 weeks (December 21, 2001), where PS3 was at 17.1 weeks (March 4, 2007), and where Wii was at 3.8 weeks (December 22, 2006).
PS3 comparisons: After 100 weeks, PS3 is where PS2 was at 21.9 weeks (July 29, 2000), where PSP was at 53.5 weeks (December 14, 2005), where GCN was at 102.3 weeks (August 26, 2003), and where Wii was at 23.9 weeks (May 12, 2007).
Wii comparisons: After 97 weeks, Wii is where GBA was at 90.1 weeks (December 8, 2002), where DS was at 70.5 weeks (April 5, 2006), where PS2 was at 98.6 weeks (January 16, 2002), and where PSP was at 154.3 weeks (November 19, 2007).
Based on the latest Media Create hardware numbers...
DS vs PSP: Weekly shares of 57.2 / 42.8 bring total shares to 69.4 / 30.6. If DS stopped selling and PSP continued at this week's rate, it would catch up in 551.3 weeks (May 8, 2019).
X360 vs PS3: Weekly shares of 57.5 / 42.5 bring total shares to 23.4 / 76.6. At this week's rate X360 catches up in 800.7 weeks (February 16, 2024). If PS3 stopped selling and X360 continued at this week's rate, it would catch up in 209.3 weeks (October 16, 2012).
PS3 vs Wii: Weekly shares of 20.0 / 80.0 bring total shares to 25.4 / 74.6. If Wii stopped selling and PS3 continued at this week's rate, it would catch up in 787.9 weeks (November 19, 2023).
So putting bits from the last two together, if Wii stopped selling while X360 and PS3 continued at this week's rates, PS3 would become the top current-gen console on November 19, 2023, but lose the crown to X360 a few months later on February 16, 2024.
Week over week, everything is down somewhat. It's most noticeable with DSL, again presumably due to the announcement of DSi being the week before and the launch of DSi being only weeks away.
Famitsu Software Stuff
Dragon Ball Origins (3186) is doing better than any other GBA/DS/PSP Dragon Ball game through three weeks. However, it will soon fall under DS's DBZ Supersonic Warriors 2 (131) which was a bit hit in holiday 2005.
Unsurprisingly, PS2's Dynasty Warriors 6 Special is starting off significantly worse than previous PS2 entries, the last main title of which was released 3.5 years back.
Super Robot Wars Z is doing decently, though. PS2 games can still do well, and not being a year-late port helps.