Ducky makes both thick PBT and stock thin ABS. If you're looking for backlighting, definitely don't go for black keycaps. As I'm sure you can tell from your TK caps, none of the black areas show backlighting, only the carved-out letter areas (Ducky does make backlighting-friendly caps like that, but they aren't the ones you linked).
Also, don't buy Filco keycaps. Their boards are good but their caps are absolutely terrible; thin ABS which shines as easily (possibly more than) those on the TK.
About the picture you linked, the best way to have that kind of effect (no backlighting showing through at all), is to buy a thick PBT set. IMSTO and other companies make these caps, and there's actually a perfect group buy going on right now (will be a while for shipping, though) with thick black PBT in printed (black) or blank, at a reasonable price.
Check it out!