For some quality machines check out
http://www.wheelingmachines.com/
If you want all kinds of info on how to build one, what to do and what not to do when building one check out
www.metalmeet.com some serious metal working talent hangs out on there. Kerry (who makes the imperial wheeling machines I put the link to above) has all kinds of post on there about how he builds and designs his wheels and shows you how it makes everything down to the adjusters etc. I've done the math and I can't make one for less than I can get a quality one but I have to factor in time, just raw material you can save some money doing it yourself but do yourself a favor and get some quality wheels, check out
www.hoosierpattern.com for them.