rough estimate of construction costs???

[Matt Concannon]

Pennsylvania - I am in the beginning stages of engineering and township approvals.  There is water, sewer, gas, and electric in the street out front.  I am looking for a rough estimate for a 30,000 steel frame building 100x300 with 22' clear span.  Anyone have a back of the napkin, rough guess on construction costs?  Interior finish will have 1 office and 2 bathrooms for my business encompassing 16k sq ft.  And I will lease out 2-3 other units.  (don't worry about estimating excavating or township costs for approvals).  I will be trying to hire a GC who specializes in this type of building to handle the whole project.