This is not official at all but I heard was pretty bad sales of 4th gen Hilux Surf (T4R) in JPN.
Also rumor came from following reasons... I picked few.

---Highlander---
Already Sales of Highlander (called KLUGER and KRUGER Hybrid) is Finished for JPN market from April 2007 but still making Hilander for US in JPN.

---RAV4---
Sales of 3gen RAV4 (long body) is finished from June 2007.
V6 3.5L engine was only for US.

---VANGUARD (Highlander x Rav4 long)---
Mixed with these 2 model. New SUV called VANGUARD but This sales is worst.

---LEXAS GX470---
It called TOYOTA Landcruiser Prado. (not Lexus)
A lot better sales than 4th gen T4R. Price range is not very diffrent from T4R too. Many auto website announce TOYOTA going to focus for only Prado in this price range in JPN.

---NISSAN Pathfinder---
2nd gen Pathfinder (called TERRANO) is no longer sold in JPN from August 2002. There are no 3gen TERRANO(Pathfinder) in JPN but US.

This Lexus GX470 and Pathfinder thing makes all Hilux fun worried.
I strongly WISH this is only rumor. I want them to make an 5th gen T4R in JPN!