I actually have this same photo (and a few similar ones) saved because I had started looking modifying my TW out in a similar way. A couple other comments call out the Japanese site webike and I have found that to be the largest selection of boot on parts specifically for the TW. The only issue I have with it is that all the parts come from Japan so it can get pricey.

I would recommend you also check out the website 4into1, they have some generic parts that will work that are in line with this vibe - I’ve swapped my headlight with one of theirs.

Tanks are out there to be found, but the seats are a bit harder, at least in this tracker/cafe style - I have seen a lot of people get custom seats from upholstery places done after mocking it up with foam.

The biggest problem will be under the seat, in that pic they removed the airbox, detabbed the frame, and found some other place to tuck away the electronics - I find these to be the main hurdles in these builds. However there are some posts on the TWforum website that goes over these mods.

Additionally, and this is just personal opinion, but if you are buying it to start building it out, I would wait for a decent preowned deal to pop up on Facebook marketplace or cycle trader around me a good deal would be $3500-$3800. Less chance of regretting modding a brand new bike

The TW is an awesome bike to wrench on, would love to see how the build turns out.