Kris, IMO, the best Dylan studio albums are "Blonde on Blonde" and "Blood on the Tracks". Each sounds very good sonically on SACD, both in stereo and in multichannel. I'd consider these to be the most essential.
"The Freewheelin' Bob Dylan" also sounds amazing, probably the best of the early Dylan albums, but I'd recommend the above two first.
While none of these SACDs can really be said to be "demo/reference quality", they are nonetheless the most satisfying SACD purchases I've made. I'd consider at least half of them to be essential... but, like me, you may find you need them all!
I finally... FINALLY... got mine in the mail. So far I've listened to Freewheelin' and Another Side (stereo and surround). The surround on Another Side is very front heavy which wouldn't have been my choice, but that's fine since I only look at surround mixes for older albums as a "bonus."
Now I get to start listening to my favorite Dylan music- Bringing It Back, Highway 61, and Blonde (Ok, I'm anal and I have to do it in chronological order).