That's an interesting idea -- I'd never considered grafting blueberries before. In case you haven't come across it, here's a link to short article and video about a grafting SHB scion on Farkelberry rootstocks (a related species that's adapted to alkaline soils).

Cousin

I have O'Neal (a Southern Highbush), and find it just as easy to grow as the Rabbiteyes.

Most Rabbiteyes send up many shoots from the base of the plant, and it seems to me that this would be a problem for the graft. The Rabbiteye that I grow that sends up the least shoots is Climax.

Benny

As Benny mentioned, how to handle new canes and keep the shrub productive would seem to be the biggest issue. I suppose that you could graft new scions to a few new canes from the rootsock each year, but that seems a bit labor intensive. V. aboreum (aka Sparkleberry/Farkelberry) has a single trunk growth habit, so that appears to be part of the appeal of using it as a rootstock. What I don't quite understand is how you'd be able to prune and maintain the grafted blueberry indefinitely in order to keep it productive.

The guy in Japan " fukuberry" on you tube grafts spartan northern high bush onto Rabbiteye rootstock. He's got videos on it. I have beckyblue rabbiteye in a 3 gallon pot that I'm practicing grafting on. This feb I grafted another rabbiteye variety on to it and I plan on trying to graft Misty, Gulfcoast and Sunshine blue onto it as well. I did 2 cleft grafts and one t-bud graft so far. As far as other canes sprouting from the rabbit eye root stock, just prune it out. I will graft the Southern high bush onto it this week and keep y'all posted if its compatible or not.

I have a Jersey - which is a Southern Highbush (I think...)

It's doing fine except that it wants some Company in the big crowd of Rabbit Eyes...

Tasty blueberries!

Thanks

john,
Jersey is a Northern Highbush.