wall wart grief

[Garry Wasyliw <was@dlcwest.com>]

>A bit (!) off-topic, but I'm so sick of dealing with 10 wall warts and 
>power
>strips.  My warts provide 9 VDC, 9 VAC, 12 VDC, and 12 VAC. 

I'm thinking that the solution might be to build a box with the various
combinations inside and connect from jacks to my gear with DIY cords.  I
can build electronic things but I think I need a little primer on power
supply design if anyone can recommend a basic web site.  I think a 9VAC
would just be a 120-9v transformer?  For 9VDC, it would be about a
120-12VAC transformer to a rectifier and some capacitors?  To reverse the
polarity (another combination to watch for) do you just reverse the two
output wires?