I like the idea and would do the same if I had the time! I hope you plan on an OG of 1.112!
I think a Belgian Dark strong ale ages VERY nicely!
I brewed the following in November 2012 and it is tasting really interesting now. It has mellowed out tremendously:
9 lbs Munich I (Weyermann) (7.1 SRM)
1 lbs Melanoidin (Weyermann) (30.0 SRM)
1 lbs Wheat Malt, Pale (Weyermann) (2.0 SRM)
2.0 oz Chocolate (Briess) (350.0 SRM)
1 lbs Sugar, Table (Sucrose) (1.0 SRM)
3.00 oz Select Spalt [2.00 %] - Boil 60.0 min Hop 6 17.4 IBUs
2.00 oz Select Spalt [2.00 %] - Boil 25.0 min Hop 7 8.1 IBUs
1.0 pkg Abbey Ale (White Labs #WLP530)
3 lbs Honey (6.0 SRM)
I'll probably use the Trappist Ale yeast next time and substitute some of the adjuncts with more grain but I still think it tastes pretty nice.