Running an air line into the lab during construction is a fairly inexpensive job. Most likely, you are going to want a chip blower anyway, so adding another line for a handpiece is not a big deal. You could then use an old, air-powered straight handpiece that has been retired from patient care for various polishing and grinding tasks, which occur in typical in-office dental labs on a daily basis.
On the other hand, a stand-alone, electric powered lab engine is certainly worth some consideration. This section currently has only one product, but it's a good one and there will no doubt be more to follow.