When I first read this I was all set to say "way too close to the Buick-Vue, bad idea", but looking at the numbers:
Current Aveo sedan: 97.6 in wb, 170 in long, 59 in tall, 67 in wide
Mini Crossman: 102.6 in wb, 160 in long, 63 in tall, 72 in wide
VW Tiguan: 102.5 in wb, 174 in long, 66 in tall, 71 in wide
Saturn Vue: 106.6 in wb, 180 in long, 67 in tall, 73 in wide
I think this could work. Add about 4-6 inches in height, and use the sedan's length but as a 5-door hatch/wagon, and it should remain plenty smaller than the "RendezVue", and almost dead on to the Crossman/Tiguan's dimensions.
I'm still not sure it's a truly good idea, but without completely reshuffling the entire small CUV model range for all of GM I can't think of a better way to do this. I do think having the tiniest CUV as a "premium" model is a good idea in order to increase profits while also letting GM get in early on the "tiny luxury CUV" market that is still wide open but that almost everyone will be entering soon.
I bet we'll be seeing this as a $22-$28k model, then the "RendezVue" at $26-38k, and the Enclave at $35-50k... to match up with the $20-28k "Skylark", $24-33k Regal, and $30-45k Lacrosse cars.