Quentin;

Late breaking discovery;

I was going through a book titled 'power supplies, switching regulators,
inverters, and conveters' by Irving Gottlieb.  It is relatively popular,
I happen to know that there is another copy at the Borders near here at
this moment.  It has some really comprehensive design info on
converters, and a number of design case studies.  You still have to
create a transformer, but many of these converters are not flyback
converters, but the more gentle forward converter.  I have mine eyes on
an example of a 225 watt line operated 15V power supply design example,
and a 500 watt example that is similar.  I think that the basic
principles in here will solve your quest.

Chris Eddy