the height, width, ground clearance of the Patriot. However, has anyone seen/heard what the WEIGHT of this vehicle is going to be? Being car-based, one would think, hopefully, it would be less than its mentor, the XJ.

I haven't been able to find anything on the weight. But, like you, I would assume it would be a lot lighter than the XJ. According to Yahoo! Autos, the FDII package won't add much weight:
http://autos.yahoo.com/newcars/future_cars/jeep_patriot_2007.html;_ylt=AuewezdfQ1bv4Fbw0mN._F Skeb8F?p=2

To put things into perspective here are the curb weights of other mini-SUVs/related cars. I'm from the USA, so the weights are in pounds ;-)

2001 XJ 4x4: 3360
Forrester: 3,165 (Manual) / 3,205 (Auto)
Rav4 Sport 4cyl: 3373 (2wd) / 3514 (4wd)
CRV: 3428

The weights were found at the respective company's websites, except the XJ's which was taken from cars.com
So I find it interesting that the curb weight of the XJ is actually lighter than the Rav4 and CRV...