M90, M112, Lysholm, Yella Terra, Harrop, Whipple positive displacement/twin screw superchargers have all been used, as well as centrifugal blowers. As mentioned above, Bullet Cars in Australia do various levels of kit.
If you have the fabrication skills, a turbo conversion may be the easiest. Swap the manifolds left to right and reversed, some pipe, a bit of welding, an integral wastegate turbo or two and you're away (some sequences have been shortened ).
http://www.mkivsupra.net/vbb/showthread.php?238361-V8-Twin-Turbo-Project
I'm sure you already know where to look, but you'll find a fair bit of info on the Australian Soarer forums (ALSC and Soarer Central), Lextreme, Club Lexus, v-eight.com (seems to have died and collected a lot of spam lately, unfortunately), and perhaps Toymods.