I ran a porteur rack awhile. Didn't do too well on that bike. Was OK at speed, but wobbly at takeoff. If you have clearance issues, can't you cut down the height of the crate a bit?
You'll need something that anchors at brake crown or headset and protrudes forward enough to give clearance for the brake assembly.

Wald probably has a rack + basket combo that'll work for you.
http://m.waldsports.com/index.cfm/store/