If you really want one, I have a Splinter that I never used - bought it and literally never fired up lol. I might be willing to let it go for the right price - message me :-)
Ryan threw in the towel and closed up shop for RBT. I believe he sold the designs & remaining parts to Unkl Mark on instagram, who continues to build some RBT vapes and sells them, so you could inquire with him to see if he has the parts to make a Splinter.
But I also see Splinters pop up pretty frequently used.