I did a search on dogpile (a search engine I use alot) which pulled up a retailer called "enjoy music" on ebay which offers 3 items for "taisho goto harp," a video, a book of melodies, & a set of strings.
Looks like an interesting instrument! I don't have it, didn't know about it, therefore it peaks my curiosity making me wish I could get my hands on one. Good luck!