There was a sweet GV at the melt this year. What I saw it do, looked pretty impressive. Not sure what mods they had, but it was big bucks. Quadawg might have more details on it as well.
That GV was a solid axle swap, very very nice... but it doesn't pertain.
As far as the question posted, the answers so far are quite interesting. As for myself, I don't know a thing about that vehicle and how it's IRS is manufactured.
Do I think IRS in general is off roadable?? YES!!!  do I know if modding a GV with no frame is doable? I don't know.
I personally think a LIGHT, STRONG vehicle with 4 wheel independant suspension would be the best possible set up for trails.
IRS/IFS has been tried by several folks, and even W. Evans went back to solid. WHY? I am not sure, I guess you would have to be able to drive in the first place to take advantage of it.
Properly set up, I contend, independant suspension would be highly superior in traction and especially ride comfort on rough trails.ÂÂ
Quad manufacturers are chasing the IRS, the new Polaris sport quad has it! (Ask Jeff|removethispart|@tireballs!!) and it WORKS!! I think it is just a matter of time before someone produces a GOOD 4wheel independant vehicle for off road (tank like Hummers DON'T count!lol). If I had the cash, and place to do it, I would make a Rockstar type vehicle with 4 wheel independant, Mike Hagen could (should) whip one out in a weekend!!!
YES on theory, and I DON'T KNOW on practicality of modding the new GV...
I personally think that two GV steel front IFS setups, installed on a SAMURAI (or even a kick) would friggin RULE (especially if you retained the inherent 4 wheel steering)