Yes Sami's have come a long way, and they all are but unstoppable when you have Toyota running gear and drive train in them. One of the guys we wheel with from time to time built this one(Toyota drive train/running gear) ran the trails with ease.
Unfortunately their size while great on the trail limits their usefulness for bringing much gear w/you, and when loaded w/camping gear for a long weekend they tend to get top heavy.
'80-85 straight axles work from either a truck or 4-Runner, but you can also use the older land cruiser FJ60 and FJ80 axles which are wider than the mini trucks, but you have to move the spring perches from below to above the axle, whereas you don't w/the truck/4-Runner ones, you can also use a Dana 44(non full size). The '80'95 truck and runner axles are narrower than the IFS rear axle, so you will need to run wheel spacers to match the front and rear track widths. You can also re-use some of your IFS components w/FJ60 rotors, there is a short discussion here
widened axle without a wheel spacer, a search should turn up more. IIRC,
Sky-Manufacturing sells a kit, I am not sure if Marlin offers a kit or who else might.
Most upgrade their oem push-pull steering to hi-steer x-over steering, which offers better control/road manners on the highway and gets all the steering linkages above the axle and out of harms way off road. You would retain your IFS steering box when using the high steer, otherwise you have to swap everything out for the original oem push-pull steering system.
Marlins SAS kit comes w/everything you need except for the axle to do an SAS, you would still need to factor in the cost of regearing the SA diff to 5.29's, a locker(if wanted), rebuild kit, as well as upgrades and the cost of the straight axle, to have an idea of what it will run you, not including installation cost. When I have figured out the cost of using off the shelf items I come up w/about $3k(ARB locker) w/o labor costs. It can be done cheaper, but sometimes it is worth paying extra to get everything you need rather than buying it in pieces from different suppliers.
