As a follow up, here's the latest version of the YotaMD key shell. It integrates the factory key as well and reinforces it with Titanium.
http://yotamd.com/products/key_fob/Lexus-LandCruiser3button.html
I'm hoping to have a few Lexus owners verify fitment on some of the non-SUVs this winter, so if you've got an LS400 or GS/SC that uses this style and are interested, let me know!
-Andy