I am an older (61 yrs) cyclist with back issues. I ride about 90 mi per week, mostly steep climbs in the Santa Monica mountains. I am looking for a lightweight frameset offering a more upright position. I plan to put A-level components and wheels on this bike. It seems that the high-end framesets from most manufacturers are designed for racing. What are the options for an older guy who wants to be comfortable but still likes to hammer?