I'm looking for the exact same thing. Any luck?
Inside I use the Bora rack and I like it a lot, just worried it won't support the weight I want for my outdoor stored lumber. I have 6-12) 2x12x12-16' and about that many 2x6's as well. Then I also have several dozen old growth 2x4's that are currently stored indoors. It's lumber I acquired for free and have been using it up slowly so down the road I may not have it, but it's always in my way and stored outside on scaffold. I want to keep the 2x12's around long enough to use a planks for the scaffold I have while I work on getting my 100yr old house repainted....hoping that gets done this year finally. I then have a mix of old cedar and treated fence boards and various other lumber as I like to make things out of them so I acquire lots of misc wood. Most the bora would be fine for, but the 2x12's not so much.
I've been looking at the cable rack stuff today, but it is pricy on the shipping, maybe I'll see if can source locally. My other thought is to go to metal yard and buy some 1 or 1-1/4" square tubing (can have them cut to length for next to nothing) then just laying it out and welding it up and going that route. But if that costs me $200 or more, I'd rather have the adjustability of the cable rack stuff.... I recently was given a Lincoln arc welder, which I haven't tried out....I need a reason to use it, but it's been years since I've stick welded.
I thought about 4 verticals up to about 6' each, then have about 12-15" in between each horizontal member. Probably have the lower 2 sets of horizontals at about 12-15", then reduce to about 10-12" up in the middle and have the last one or two at 6-10". Maybe put a hook on the top of the verticals so that I could attach a tarp to it to drop over the lumber to keep out of weather.