I can respect the challenges (technically and artistically) in designing around existing parts. I would maybe take a "glass half full" outlook philosophically in approaching it as a challenge - aspiring to greatness in spite of adversity, so to speak.
Designing new products around existing parts SEVERELY limits your design and gets old (for me anyway) after awhile. I actually originally designed my frame to accept rubber wrap arounds and hated the final design. Ditched the entire design started from scratch and really dig the final design.