Check out RAID0 there is a part about booting off a RAID device.  I have never 
used RAID0 so I don't know how serisous it is about the "devices approximately 
the same size."

http://unthought.net/Software-RAID.HOWTO/Software-RAID.HOWTO.html

You might be better off just finding a different mountpoint for the other 
partition (/home maybe).

Austin

Rob Wultsch wrote:
> I have a sun sparcstation 20 that has 2x 1gig hard drives. The first 
> drive I created a a single bootable partition on, and the second I 
> created with the first partition being .5 gig and type linux native, and 
> the second is .5 gig and linux swap.
> 
> I have mounted the first scsi disk as root, and the debian installer is 
> asking where I would like to mount the first partion of the second disk.
> 
> Is there anyway to seemlessly span the entirety of the first disk with 
> the first partition of the second disk all mounted as / ?