Luvs - white stitching would be possible - it would however be a lot more difficult as it would show every little difference in any of the stitches, and stitching in 16/17 stitches to the inch is bad enough already ( believe me I know )
Kitten - putting one pearl/jewel/stone would be no problem at all - the browband below has stones set apart to look different. PICT0049.jpg PICT0052.jpg
One sad fact is that in the world of today there is little room left for what can be achieved - most people either want something quickly ( which is not always possible - as I said it has taken 6 hours just to get the pattern right ) or they want something cheap.
You cannot buy the tools to stitch at 16/17 per inch anymore- I had to get mine specially made, the needles and thread are also slightly bigger which makes it harder. I have seen , and indeed have , some of the work that was made in Victorian times, over 100 years ago , and what is produced today does not compare , other saddlers call me mad for stitching like this , but in times past this type of work was the norm not the exception .