please dont. the transformer will provide isolation.
You can use a autotransformer (ie an inductive voltage divider) to step the voltage down to a suitable level and then rectifiy it as normal. The use of an autotransformer arrangement is prefered over a plane resistive divider since you do not have as much resistive power loss/heating, you just get reative loss in the inductors. you just need to do some maths on the reactive component at main frequency.
The company Vircor www.vicr.com do high voltage -> low voltage DCC converters, just rectify the mains and pass it into the vircor. These are isolated so are safe - but cost a bit.