Slipknot's suggestion of Boosblocks in very well taken: 24X18X1.5 $86, 24X18X2.25 $107. I have one of their blocks, put to the more conventional use of a cutting board -- very nice. The blocks come with a very minimal oil finish, which might be an advantage, depending on your tastes. You might try to get Boos to ship unfinished, if you want to stain. Boos has a lot of local dealers, which could save you a reasonably hefty shipping bill.
In contrast, a local mill here in St. Louis asks for $175 for a 5'X2'X1.5" piece, which gets you your three shelves for a bit less than Boos, but with more work at your end, depending on how much sanding is required.
On the rods, another source is Mutual Screw. They don't seem to do brass, but they do zinc plated steel, and $66 gets you 2 very beefy 1.25"X3' rods (http://mutualscrew.com/products.php). A decent bit less than the brass, but less attractive. Do the metalugists out there have any thoughts on zinc plating?
One possibility for the footers is the relatively inexpensive spike kits sold by Adona and others. These might be mounted to the inside of the rods on the bottom shelf. Thoughts on that?
Two questions on technique:
Sounds like you go 1/16" larger than the rod size with the holes. Is a drill press mandatory?
Some people suggest clamping the shelves together and drilling the holes through all the shelves at once, to assure alighnment. Any thoughts on this? Drilling a hole through five or six inches of maple is no joke, even with a drill press.
Now, the big question: This is not quite a budget DIY project, say $500 for a nice three shelf rack, and very possibly more. $500 doesn't get you into the highest end stuff of course, but it does get you into some stuff that people seem to like pretty well, like a three shelf rack from SolidSteel (new). I like the look of the flexi design, but can anyone weigh in on the bang for buck of the overall project, regards both visuals and sonics?
Thanks to everyone; this has all been very helpful!
John