I brewed a 10 gallon batch of sour brown about 6 months ago that has come along quite nicely. I did something similar to the OP's idea, but not exactly. For both 6 gallon carboys, I used a clean ale yeast. Once high kräusen started, I added 2L starters of Brett B. and 1 ounce of oak cubes to each. After a few months, I bottled the batch with just sacch and brett, and added Jolly Pumpkin dregs and more oak to the other one. It has since formed a pellicle and smells wonderfully funky.
Here's the recipe if you're interested:
11 gallons total, ~88% mash efficiency
6 lb 2-row
4 lb Munich
6 lb white wheat
1.25 c-60
1 lb c-120
.25 lb chocolate malt
Mash at 155 for 45 minutes, then add 2lb of acid malt, mash 45 more minutes
80 minute boil
2 oz. hallertau 3.2% @ 60
1 oz. debittered whole hops @ 60 (I don't think this is necessary)
The beer tasted pretty good early on, but the added complexity and aromas from the brett and dregs have made this a winner in my book. I just need to stop taking samples from the remaining carboy that has the dregs. The bottled batch with just sacch and brett is also very good.