Howie
I have the Dekker Supreme. Nice bag, good size and it has about 1.5 inches of foam padding all around, that is why it has that nice shape you see in the pictures. But all that foam does take up some room. Take the foam our and you can pack a lot more.
I got the bag for Deb when she flew to TN to meet me, found out it is awkward to carry for any distance with it packed.
Keep in mind, get the biggest bag, load it up and you will feel a significant difference in the way the bike feels and handles. The CoG jumps up quite a bit.
Personally I was thinking about my next bag having wheels like the Dekker roller, but it is big, and if you have the TP spoiler it hits (mentioned on their website).
You said 2.5 weeks for Sturgis. Is Binx going?
If you are traveling solo I would consider the back seat bag
http://www.t-bags.com/detail.aspx?ID=3&SelectedCat=4Doubles as a back rest.