Possible to merge drives in Vista/W7?

As you know, XP cannot see the Drobo as one large drive. It splits into two 2TB drives. This is annoying, and I will be moving to W7 soon. My Drobo is 99% full. Is it possible to merge the two drives under W7 again without formatting? I hope there’s some sort of a software that can do this.

nope. offload, re-partition, re-load.