eMachineShop.com

I supposed we'd have to try this for ourselves, but eMachineShop.com looks intriguing. Upload your DXF file and wait for the little elves to send you the part. (We're scared by the "Step 2: Draw your part using the easy-to-use design software" on the their demo page, but hey, if it's the right tool for the job...) [Thanks to _nando for the tip.]
