It depends on the design. Most units described are readily available.

Don't spend the money to match the exterior finish of the cabinetry on the cabinet interiors, you want the interiors to be easy to clean and a light material so you can see what is inside them. No one will notice or care if the interiors match the exterior (these days it is pretty much industry standard that they do not match) If the cabinet doors have glass fronts then definitely match the exterior or use a pop of paint color on the cabinet backs.

I suggest you follow the step-by-step guide for creating storage cabinets under the bathroom sink. Take proper measurements - Measure the available available space in height, width and height. Cut Plywood to size - With a circular saw and framing square, cut all the required pieces out. You can use a sliding compound saw as an alternative. Attach the base and sides - Start assembling the sink cabinets by placing the bottom piece of plywood sheet on a flat surface. Attach the back and top boards - Place the plywood sheet for the top part of the cabinet and attach wood screws to connect it to both the sides. Turn the back faces of the cabinet upwards. Keep the back piece over the structure and fix it into place with wood screws. Attach shelves - Place the cabinet in an upright position to install the shelves. Slide a shelf into the structure so it is flush against the back. Attach door - Keep both hinges of the door on the same side of the plywood sheet. Drill them using wood screws into place. Now keep the door over the cabinet structure, extend the hinges to one of the side panels and fix them to make them secure. Fix a hasp closure on the other side of the door, placing it in the center of the hinges.

if u are interested in art work.. you should definitely go for some bastar art pieces.. beautiful vases in contrast colors to the dining area will also comprehend the look