Check with Remco. They do have equipment for the new 2005 Xterra. They've been making stock vehicles "towable" for decades. They make axle & driveshaft disconnects as well as external transmission fluid pumps.
I was in your situation a year ago. I traded my 2000 Nissan Crew Cab for a new 2004 Jeep Wrangler Sahara. The big difference is the Jeep was designed to be towed. Put the real transfer case in neutral, tow it as far and fast as you dare. No miles accululate on the odometer. Very simple to add brackets for towing.
Details on how I modified my Jeep
at this link. Due to the weight, ease of towing, the Jeep is a better choice. That's why it's one, if not THE most towed vehicle behind motorhomes.
I traded in my Jeep last week for the Xterra. I'll be selling my motorhome soon, so I no longer need the Jeep. The Xterra is a much better daily driver while still retaining the ability to go off-road. However, if I was keeping the MH, I'd be keeping the Jeep.
If you really want to keep your X for this purpose, check the max weight of your MH to make sure you aren't exceeding your limits, then call Remco, or
visit their website.