I would say Toyota really started the upscale marketing with the original FJ80. By the time they decided to go to coil springs, leather interior, etc, etc, that was when it was more than a basic SUV and price started to reflect that.
However, I think there were some pretty significant price increases in the early 1990s, and its hard to say what caused this. There were some tariff issues with Japanese products about that time. And the SUVs were just becoming super popular while the sport's car market, which was the "in" think in the 1980s and early 1990s was just dying off. So, those could be factors for the price increase back then.
This is the base MSRP price from what I could gather online. Remember this appears to be base, without options. All numbers are rounded off. Prices are in the U.S. market: For current inflation numbers add about 3.7% to the 2006 figure.
60/62 series
1983: $13,000 (40 series: $10,000) Inflation 2006 dollars: $26,000/$20,000
1984: $14,000
1985: $15,000 Inflation 2006 dollars: $28,000
1986: $17,000
1987: $18,000 Inflation 2006 dollars: $32,000
1988: $20,000
1989: $21,000 Inflation 2006 dollars: $35,000
1990: $21,000
80 series
1991: $24,000 Inflation 2006 dollars: $36,000
1992: $27,000
1993: $32,000 Inflation 2006 dollars: $44,000
1994: $37,000
1995: $39,000 Inflation 2006 dollars: $52.000
1996: $40,000 (Lexus LX450: $48,000)
1997: $41,000 (Lexus LX450: $49,000) Inflation 2006 dollars: $51,000/$61,000
100 series:
1998: $46,000 (Lexus LX470: $49,000)
1999: $46,000
2000: $51,000 Inflation 2006 dollars: $60,000
You can see the biggest price increase happend during the 80 series production run, where price literally doubled or more. Don't forget that most 80 series were sold for well above base price, because they were optioned out. My 1995 model based around $39,000 but sold for more than $48,000 and didn't even include things like lockers, tow hitch and roof rack.
The 2008 Land cruiser base MSRP is $63,200, but the important thing to remember is that there are literally almost no options available.