DCRA will not recommend contractors, officially. If someone recommends a contractor -from within DCRA- that person will be doing it only for his own benefit or for the benefit of the contractor, but that is not amongst the official duties of DCRA.
Usually your architect/engineer/designer will recommend a contractor with whom he/she feels comfortable working.
Your design professional will also think the whole space in a three dimensional way, and usually will offer you a few options to go about solving the problem.
Have a budget in mind, a realistic one, before you talk to a contractor. It will depend on the size of the dig-out, and the construction methods employed, and also on the particular conditions of your property.
Feel free to e-mail me at odcstudio AT aol DOT com.