I think integrating the board into the table makes it a much nicer looking piece of furniture. It will expand your market beyond the chess lovers niche toward something all home owners would want. Of course, targeting upscale luxury markets will also drive up the sales price.
Other than that, I think your woodwork looks stunning. It will have to look non-standard with grandmaster-size pieces. Walnut is great, maybe something like suar wood if you can obtain it from a sustainable source.
Personally I think the one Richcolorado posted at the top of his post, saying 'i love this board', is the most beautiful one color-wise. So for me it would have to look modern, with the board flush to the frame and tabletop. Also consider smaller sizes for small apartments, dorm rooms, non-US homes, etc. My small European house, for example, literally has no more room for anything the size of a chessboard.
Your boards are very nice especially the ones with wide borders. I prefer wide sides or borders so there is a place for the captured pieces. I prefer the playing surface to be either flush with the sides or or lower. I prefer natural woods with the grain not too bold as bold grain is distracting. Grain direction can be either along the pawn play direction or across. I prefer in the pawn play direction but it should be the customer's choice. The greater the color contrast between the light and dark the better. Tropical walnut and maple are good choices.
I made my first board, which is also my current board in high school over 50 years ago. I understand what goes into making a board, especially getting the squares to match up. I suggested Tropical walnut instead of American black walnut as it tends to be darker. Finish product choice is important since varnishes can age over time. I recently refinished my over 50 year old playing surface since the varnish had yellowed reducing the contrast between squares. Polyurethanes did not exist back then.
I trust this will help you in your work.