Front mech could be a 28.6mm band on Rival, and swap out the S500 levers for Tektro V levers. XT V brakes and a medium cage rear derailleur with a 11-34t cassette giving a low gear of 34/34 or 27.3 GI up to 50/11 or 124.2 GI with 37c tyres and 172.5mm cranks.
Talk to me about the Microshift bar end shifters.. why those over Shimano/Sram?
cheap and black