[Amps] power supply transformer

[kg7hf at comcast.net]

I am not sure I'm sending this correctly, but here goes.

I want to build a 120 volt DC source that can supply ~35 amps.  I would like to have the primary either 240 (typical) or 120 v AC.  It doesn't have to be regulated, but must be somewhat well filtered.   My question is about transformers, this type of transformer does not seem to be a common item.  Has anyone ever heard of a 240/120 primary 120 secondary at these high current levels?  

Why do I need to use a transformer in the first place, can I not simply rectify and filter the two legs of the 240 without a transformer?

Thanks
Paul (KG7HF)