Do you like your Sanus, VTI, or Salamander rack?

Salamander is sturdy enough IMHO, but far from rock steady.
I like it better than a Mapleshade I tried, but I'm of the "Rega" more mass just stores unwanted energy school.

Schubert, are you saying you think the Salamander "sounds" better than the Samson? Did you find it more user friendly to set up or more aesthetically appealing? I'll admit I believe in Mapleshades approach after using a 4" block under the turntable.

All of the above, 4" works under sone tables not on others.

I have the Salamander Synergy audio rack with 6 shelves plus 1 pull out shelf for my laptop. Previously I was using a Sanus stand I bought from Music Direct. I noticed an improvement right away when upgrading from the Sanus to the Salamander Synergy rack. It's hard to describe but the system just sounded better all around. I have no experience with the Mapleshade racks or the Walker racks, but an audio buddy in another state told me the Mapleshade rack "sucked the life" out of the music. I have not heard his system so I can not verify this. I would never spend the kind of money the Mapleshade or Walker rack costs. If I had that kind of money to burn, I would upgrade one of my components or invest it in more music.

My ancient solid welded Target is probably better than any of them

and so is Sound Anchor IMO. Hard to find used, but reasonably priced to have made, considering their "last forever" quality. If desired, the Sound Anchor component stands are sturdy enough to put on heavy duty castors so you could roll the whole rack and system out of the closet for cable changes, etc.

I want to move the equipment into the closet

If cost is a big issue, why not simply nail shelf supports to three sides of your closet and use them to support DIY shelves of your choice? There would be many options from simple plywood shelves to plywood/mdf sandwiched shelves or, if you want to go all out, you could concoct a constrained layer shelf using a sandwich of black gatorboard, mdf and aluminum (sort of like the Symposium Svelte Shelves). The shelves could be permanently anchored to the supports, which would be screwed into the wall studs, thereby using the framing of your house, and not the more flexible floor joists, to support your system. I suspect the result would be quite sturdy. By leaving a couple of inches (or more) of space behind each shelf, you could more easily manage cable runs.

My point is, if you can't afford the quality you want, why buy something of questionable stability/quality, when you can construct something better to meet your needs?

Good luck.