If they are PVC the easy way would be to grab one of the cheap wood burning kits. Then a set of the number heads they make for them. Let the thing heat up and emboss the number in the cover and tube. Let it cool and fill the embossed groove with nail polish. You could even pick colors to match the alloy/material in the tube to make it a bit faster. IE: white for aluminum, black for steel, yellow for brass, silver for stainless and so on. The print out a chart with the numbers, alloy, amount. Use a laser printer if possible as that print holds up better than an ink jet. Slide the chart into a sheet protector and have fun.
Heres my cheap way of doing it with what you have got lying around....... Variation on the wine rack concept as mentioned - You mentioned you scored a heap of 4 by 2's a while ago. Layout a grid, of sufficient size to hold each tube. Mark all the intersections. Alternatively notch each one so there a nice, easy fit. Make 2 sets of these, with 4 lengths of timber, nail them together in alignment so they are the (nominal) distance apart. Nail a good strong piece of ply on the bottom. Suggest you make it as a square - easier, and you can bang surplus casters on it if you want to...
Now, I will admit this sounds like a lot of work. BUT......If you got a working vertical mill, hopefully with a bed long enough to take the length of one side, tis simple. Set up one piece, stick a router bit in your mill, and run flat out. Cut each notch halfway, and set the depth stop on the mill.
When this is done, clamp it in alignment on your mill table. Clamp well. Butt the other pieces against the master one, use G-clamps (or anything) to hold them in place - your not looking for micron precision here. Just mill them out, as many as you can fit at the time across the bed. .... Do a drawing/sketch, number each piece so you dont get mind stuffed by all the bits of wood lying around.
So. There. Would give ya a hand if you weren't a continent away.
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