I doubt that you will find a 3000 sqft lot that doesn't have a Townhouse on it:
That sounds like a lot designed for a Townhouse, that would be part of a Development; the lot wouldn't be up for sale separately, because it is PART of the Development.
Most city lots would be 8-9,000 sqft minimum. (A 1/4 acre lot is about 10,000 sqft).
If you are serious about this; please contact a Realtor and do it right.