nelson platform bench???  

Herman Miller originally...
Herman Miller originally manufactured many sizes. More than 3. The best is what suits you.

That's not true, Stephen...
Don't listen to him. There is a definitive best.

Please..........
In the 1949 initial catalog the following was available:
4690 48" by 18 1/2" by 14"
4691 68"
4692 72"
4693 102"
In the 1952 second catalog:
4690 48"
4991 53 3/16"
4691 68"
4692 72"
4992 92"
4693 102"
All were available either natural wood seat and ebonized legs or all ebonized
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In the 1956 catalog;
4690 48"
4991 56 1/4" (note the slight change)
4691 68"
4692 72"
4992 92"
4692 102"
with the 1956, metal legs could be substituted for the wooden legs.
Note that 4992 and 4692 had three legs.
Hope this helps

"Note that 4992 and 4692 had three legs".
I assume you meant three PAIRS of legs, meaning six legs total.

Well...
Each leg is a single piece...

I think
I think the 48" is the most versatile as well as the most aesthetically pleasing. But thats just me.

I have the 60. Sometimes I wa...
I have the 60. Sometimes I want the 48.

The 48 and the 72 have proven to
the other all most versatile and best selling sizes.
The 48 makes a nifty coffee table and is very versatile and the 72 is long enough to be a proper bench and works well with any basic storage pieces you might have to put on them,
Some of the sizes were discontinued when the basic storage pieces were discontinued.
Also, the tapizoid wooden "legs" equal two legs, so the 48" bench has two of the wooden legs, not four.

Believe it or not....
I just called Herman Miller customer service, and they have been asked numerous times to bring back some of the Basic Storage pieces, and they are ACTUALLY considering it!
I suggested:
4610 24" wide, 14" high, 18 1/2" deep
4620 40" wide, 14" high, 18 1/2" deep
4701 24" wide, 24" high, 18 1/2" deep
4606 34" wide, 24" high, 18 1/2" deep
All of the above should be available in one wood tone (to keep it simple), and all should be available either with or without metal hairpin legs. In addition, once the carcasses are produced, then they could either be easily fitted with either shelves or drawers (which would make them easy to use for book storage or as chests of drawers.
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Four reasonable bookshelf/chests sizes, available with either shelves or drawers and available either with or without hairpin legs.
Boy, I bet they'd sell really well, provided they are at a reasonable price.
There's precious few beautiful bookshelves and chests of drawers available currently, so i think they'd be a smashing success.
The person I spoke to didn't know when HM will reintroduce any of them, but they ARE looking into it.