That's an interesting idea, but it would probably be cheaper to buy a real bench power supply, e.g. Mastech. Also paralleling probably wouldn't work well; for instance you might end up with one power supply providing most of the power. For details on running power supplies in parallel, see http://www.weidmuller.ca/system/files/webfm/downloads/pdfs/l...
Or worse, since the supplies' outputs will not be precisely identical or vary over their tolerance range in in sync with each, one supply could end up injecting current into another and cause damage. Such power supplies are generally designed for a specific load impedance, and connecting the supply outputs in parallel can effect a smaller load impedance than tolerable.
