We don't have the form you're looking for.
I was able to find the following form from the Red Cross site: http://www.redcross.org/images/MEDIA_CustomProductCatalog/m10942433_Donate-by-Mail-Form.pd f
It doesn't have a designation specific for Hurricane Sandy, but it does have a 'Disaster Relief' option. You may be able to find something that's an even better form by contacting the Red Cross directly.
Please let me know if I can be of further assistance and thank you for helping those who were affected by the storm!