Is the Penang in Reston still open? If so, you might be able to get Laksa there. I can't guarantee how good it will be though.
Address: 11964 Market St, Reston, VA 20190
Phone: (703) 787-8988
I heard that the Penang in DC is closed because of a fire...so your next best bet is the Penang in Bethesda, MD. I took a quick look at the menu of the Bethesda location and I see they have Assam Laksa. Assam Laksa is a North Malaysian version of Laksa. It is a sour version of Laksa and there is typically little or no coconut milk. Not sure what type of laksa you are looking for. The laksa that I dream of is "laksa lemak," which is made with coconut milk and ohhhhh so good!
4933 Bethesda Ave, Bethesda, MD 20814