It is possible to have a builder that excavated and placed full depth walls in the area of a crawlspace. However the majority that I have seen are not. It is not impossible to excavate the area but it can be a daunting task which could be very costly. The easiest of which would be sledding or conveying the dirt out. But its not just that easy. The trick is not disturbing the soil below which the footings rest. Loads transfers from the footings are straight down and at a 45 degree angle. You cannot disturb any of the soil in that 45 degree area(undermine the footings). It is possible to excavate the center of the space, support the center of the house and add new footings and walls. But this is a costly endeavor. One of which I would think you would need to get a house for a super deal to even consider. If you still like the house but choose not to excavate, keep in mind that crawlspaces are known for moisture problems. There are 2 types. Vented and non vented crawlspaces. Non vented typically require conditioning of the air such as with a dehumidifier. A vented space has vents for cross ventilation. A crawlspace should have 1sqft of ventilation for every 150sqft of space. There should also be a 6 mil thick poly vapor barrier on the ground, overlapped, and sealed along the walls. Most people then add gravel atop this for protection.