29V at 6A DC is what it says. You would be able to reduce the DC voltage to something in the low 20s or so by selecting the appropriate primary taps, you will still get 6 A with a FWB rectifier. You really don't want too much more voltage than you need, because it will make the power dissipation go up, and thus heatsinking gets harder. If you are "racking" parts, or hanging them from hooks, you will want 10-20% more voltage available to compensate for the connection loss. If you tightly bolt the connection to the work, you won't need this extra voltage.
I notice that MPJA also lists a 13.5 V 20 A transformer, that would provide 17-18 VDC 10 A, including diode losses, with a FWB.
I havent heard anyone talk about an enclosure yet, only a fool would leave any of the 120 VAC wireing exposed. You also need a fuse or circuit breaker in series with the AC line input.
You guys have a ways to go before your're ready to select MOSFETs. I will make some minor refinements to Don's design besides MOSFETs, to make it better suitable for anodizing. Give me a few days.
I would suggest
www.digikey.com or
www.jameco.com for the MOSFETs. opamps, resistors, etc. that you will need. You will pay through the nose at RadioShack, and their selection sucks.