A few years ago I had the same problem with my toyota tacoma, they don't make an extendable towing mirror for import trucks. For a while I used the universal strap-on style mirrors on my stock mirrors but the vibration was so bad I was getting motion sickness LOL.
Just within the past year, a company started making a mirror that bolts it place of the stock toyota tacoma mirror that flips up to become a full towing mirror like the fullsize dodge ram mirror.This mirror may fit on your landcruser with some modifing of the base. Online with 1a auto parts.com, I saw it listed under tacoma towing mirrors.
I did something a little different because I didn't like what was on the market.
I installed powervision mirrors.com from a 98 chevy which are power extend/ power retract plus full electric mirror adjustment.This modified set up is alot of work and is the most difficult to do.
The base of the chevy mirror was smaller than the stock toyota mirror, so I drilled new mounting holes in the toyota door and used a 1/4 semi-truck mud flap as a gasket/ molding for the new mirror. I wired the chevy mirrors to my stock toyota mirror adjustment switch for the stock look of my dash because the mirror adjustment uses reverse poliarty to move the glass I just had to hook up the wires using a toyota and chevy wiring diagrams
I installed a seperate switch for the power extend/ power retract function I found a switch that fits in one of my knock out blanks in the dash. Let me know if you have any questions.