There's a William (Bill) Brunner from back east who's a cycling coach but raced in Pasadena for a time in the 1970s and has degrees in mechanical engineering. He's on the United States Bicycling Hall of Fame board of directors:

About Bill Brunner - Bill Elliston Event Announcing & Coaching

It doesn't appear that he's very tall, but perhaps he dabbled in frame building? Might be worth reaching out.

-Gregory