You didn't answer my question - Do you have proof (in the form of a photo, promotional award letter or Mandarake notice) that the Miyazaki and Oda sketches are legit? Because, even examining the Oda shikishi, I see a couple of glaring errors. Look at the E in Eiichiro - Why is it shaky? Doesn't an artist know how to sign their own name? It looks like someone who isn't familiar with cursive wrote that.
Heres a video of Oda signing -
http://m.youtube.com/watch?v=23iIjnnv9Qc
My concern is that these two artists are two of the most counterfeited artists out there. When two shikishi pop up that look exactly like ever counterfeit on YJ, I get concerned especially when I've asked you for solid proof on both of these items and you have yet to deliver. When I see people selling questionable sketches, I become concerned that someone who is unfamiliar with authentic artwork from either artist will be duped into buying what they think is an original sketch when it's not.
True, I am a collector. I care very much about authenticity and provenance of my own collection, which is why I do my best to research items I own and take pictures of the photos that create this artwork. However, as a responsible collector, I feel that if you have a counterfeit, you should do the responsible thing and either inform potential buyers it is counterfeit or not let the item leave your possession, either by keeping or destroying it. Reselling the sketch to recoup your losses is irresponsible at best.
Would I be interested in buying either sketch if they were authentic? Possibly, but not without solid proof.