The simulator available on the NOW website allows for 56 disks of 1GB in size, however the freebsd UFS filesystem where the simulator files are located is not large enough to accomodate those 56GB of data. If one tries to write more than 30GB the simulator will crash and won't you won't be able to restart it again without extending the underlying partition.
I've hacked the SIM vmware images available from NOW by extending the vmdk disk, the freebsd slices, and the UFS filesystem, the number of disks have also been increased to 56.
Notice that aggr0 is 32bits, if you plan to use features such as compression you can either create a new aggregate with the remaining 53 disks or migrate aggr0 into 64bits.
While the simulator is not suitable for serving data, it is quite usable for testing netapp software or custom made scripts that require snapshots, it can be used for lab testing of different applications: oracle, sqlserver, exchange, ESX.
You can find procedures on the web to install ESX on vmware workstation, and then use NFS datastores served from the simulator. It is then possible to use this setup to test SnapManager applications such as SMVI, SDW/U by building a light VM into the virtualized ESX server.
(*) don't expect it to run at neutrino speeds! the experience will be more like taking a 2am night bus on a saturday night from central london to brixton.
and note that this image is only available to NetApp staff:
http://web.netapp.com/~jcosta/AH45-ONTAP-Simulator-8.0.1-56disks-of-1GB-on-bsdslice-with-72GB.tgz