I don't have any experience with the particular products from Reid Supply, however, keyed shafting is a commonly available item, I know we have a couple places locally that we can get it. Look around for places that deal with "power transmission" or "industrial supply".
I certainly would avoid stainless steel unless there is a compelling reason to need the material properties (and I can't think of one in a FRC robot, at least not until we finally get the long awaited "water game"). It's a lot easier to cut 1018 steel.
Here are a couple other places you can get it besides McMaster:
http://www.fastenal.com/web/search/p...N-gj52ws&Nty=0
http://www1.mscdirect.com/eCommerce/...scrNtk=default
And a Google search for "keyed shafting" will turn up a lot more possibilities.
Personally, I hate keys and much prefer to use hex shafting whenever possible. This hatred goes back 20+ years.
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