You can make your own. I like the Toroidal transformers by Plitron
http://www.plitron.com They are like getting two transformers in one.
You can get the standard Plitron #097018201 Output is 35 VAC at 8.93 Amps. Connect the output in parallel to double the amps to get 17.86 Amps $66.02 plus shipping Should give you 49VDC at almost 18 Amps.
Get the Cap from
http://www.mouser.com you will need at least a 30,000 uF cap so get the 75 Volt 37,000 uF cap
#539-CGS75V37000 $38.14
Last is the Bridge Rectifier. Mouser has them too.
#583-MP252 200 Volt 25 Amp rated for $2.77