You can always get ideas from Interior Design tool magazines and catalogs. Become inspired by the small bathroom sinks that they display. Pay attention to the details of the bathroom. If you see anything that interests you, take notes of you. You can probably end up doing those designs yourself.
If you have a deadline, make sure that you confirm it with the contractor. Also, get in writing the time frame he promised to have the job done. Try to be reasonable however, as some bumps in the road may appear with any home improvement project.