The 3D printing suggestion is a great one. If you do not have access to one yourself, and are close to a College or Technical College, check with their Engineering, Mechanical Design, Tool and Die/Mold Making programs. Often times school departments welcome projects that students can reverse engineer, draw up, program, and fabricate. Limiting criteria is usually only a possible patent, or trademark infringement, which these button caps will not be violating.
It is close to end of semester at most schools now but contact them to see anyway. Some students may do it as a "Capstone" semester project, or schedule it for first thing next semester. Generally, most departments only look for a small "donation" to pay for materials, and they are glad to provide the real world experience to their students.