Sandman's site is up, he takes it down at night. But I don't think he does white decals any more, his ALPS printers are too expensive to maintain.
You could try either Tango Papa's or Stickershock 23. Try Emailing Tom at Tango Papa's first, I understand his business is seasonal. He has the waterslide decal listed in his $13 section, look under V3. And Mark at Stickershock 23 has the vinyl decal listed but at 4" and up. Email him, I'm sure he can downsize it to 2.6" and give you a quote. YORP has the decal scans with the plans, but it would be very difficult to home print those since you would need a printer that can do white ink, plus the background of the scan is blue.