You can’t throw a rock without hitting five nail salons in Manhattan, and according to the Yellow Pages, our fair metro area is home to 1,277 such businesses. But have you ever tried to get a mani in a smaller city — Boston, Philadelphia, or (God forbid) Hartford? Case in point: The rest of the nation is apparently suffering from a void of salons offering quick, clean, and inexpensive manicures. Enter Sue Thirwall, the Boston-based CEO of MiniLuxe nail salons, who is hoping to “Starbucks the nail salon” with the brand’s Luxe Manicure. Her business plan has a well-manicured lady (or gentleman) out the door in 30 minutes for less than $20. This just might work.