I've been working on a similar power supply for an as-yet unbuilt system. So, one caveat: my knowledge is all theoretical, at this point.

From searching ebay and surplus shops, I've not encountered much in the way so-called 'isolation transformers.' That seems to refer to transformers that don't change voltage from primary to secondary, e.g. 120VAC primary, 120VAC secondary. I have seen a number of 'control transformers' and 'general purpose' transformers. Typically (in the US at least) these seem to be 480VAC or 240VAC primary (or both) and 120VAC or 240VAC secondary (or both). If you have a 240 volt circuit available, this would probably work best.

I like to use the web form calculator at Online Calculator .:. Linear Power Supply Designer

A few notes on usage:
1.) This calculation seems to be extremely conservative regarding the smoothing capacitor volt rating requirements (165vdc output suggests 300vdc rated caps. Elsewhere I've seen it suggested that a 20% margin is fairly safe to assume).
2.) A high voltage supply probably would not need regulation, so ignore that parameter. Rather, if you insert the max desired voltage ripple, it will give you a reasonable capacitor size value (i.e. 165vdc output x 10% ripple = 16.5vdc voltage in the 'regulator' voltage drop field).
3.) I've heard it suggested that rectifier ampacity ratings should be at least twice what you expect to use. I've bought 50 amp bridge rectifiers off ebay for a couple dollars a piece (albeit from china). There are some 150amp modules I've seen for less than $20. If your volt ratings are enough (600v and 1000v units seem common) and you amp ratings are sufficient, it apparently comes down to having a big enough heat sink to keep it cool during operation.

I plugged in 37 Amps and it suggests an 8kva transformer is necessary. I've seen them on ebay at 7.5kva, 10kva sizes, mostly 480x240 primary, 240x120 secondary; I think these would work well. Since units this size weigh about 150 lbs, what kind of a deal you get might depend on whether you can find one locally.

Just curious, what drive are you planning to use? 25 amps per axis is some pretty serious power for any project. Is this for servo motors?

Let us know how it turns out when you get it figured.

-b2b