starbucks has very high quality stainless steel vaccum-sealed mugs in the fall but they often sell out. i bought 2 over a decade ago and they are both still in use despite a few falls at speed. my only problem with steel coffee mugs has been that conventional bottle cages tend to loosen or snap from the abuse.

i've found that these cages work the best and last the longest when you ride with heavy metal bottles:

http://www.lezyne.com/en/products/bo...es#!power-cage