Flipside is good, but $15 more, Primus Minimus has a rain cover.to ts:
maybe can take a look at the lowepro flipside...quite a gd looking bag...and fits most if not all of your criteria...also have an option of carrying a tripod...cost about 135+...still within your budget..
ehh....dun think so...the mount of the lens is quite strong...and the bag also got provide support to the body when you placed it lens down..so no worries bah...