well imtishal, the truth is that anything is possible... i'm sure you can transplant an IFS lux setup on hardbody, the right way to do it would be to get a half-cut for a lux, vigo, prado, surf and mate that to the hardbody chassis. Make sure you have a good welder (preferable argon welder) and that your chassis joints are dove-tail joints and (not straight joints) and that you reinforce the welded areas. suhaib can brief you on a encounter of his with an FJ40 with a IFS prado setup upfront. this isnt going to be cheap but will work quite nicely.
going the solid axle way is easier and has plenty of options...although the rig would end up being more of a rock crawler than a desert racer... i like the city saddar waalas as they are open to pungas... go there throw some ideas around and you might come up with a workable solution...
i would also look up stuff thats developed for nissan frontiers and titans...dont know if those could be used on the hardbody. nissan did have plenty of support for the hardbody back in the day but not anymore... you'll find some stuff on "infamousnissan.com"...also i remember coming across a hardbody prerunner build somewhere as well... happy hunting