Super thin, plastic, legal size, on wheels

What country?

Hi Viki,

The U.S.

Is that or file storage or tools or something else?
Must be with handle to carry in hand too?

I do not know about the sizes, but for portable file storage with wheels, you may get something like:
http://www.staples.com/Staples-Expanding-Folding-Crate-on-Wheels/product_440122
https://www.overstock.com/Office-Supplies/Storex-Portable-File-Box-on-wheels/10856359/product.html?refccid=ZN3X4GICNGHK4MKJYGPRTGB5NM&searchidx=2
https://www.overstock.com/Office-Supplies/Storex-Premium-File-Cart/5558946/product.html?refccid=ZN3X4GICNGHK4MKJYGPRTGB5NM&searchidx=12
https://www.amazon.com/Storex-Premium-File-Cart-STX61507U01C/dp/B009JY00YE
https://www.walmart.com/ip/Collapsible-Heavy-Duty-Folding-Office-Cart-with-LID-Mobile-Filing-Cart-by-Unique-Imports/174381306
https://www.walmart.com/ip/Safco-Mini-scoot-Mobile-File-Cart-4-X-2-Caster-Steel-19-X-14.8-X-14-Black-5371BL/40207429
http://www.samsclub.com/sams/foldable-rolling-car-crt-03622/prod19720408.ip?xid=plp1777-offi:product:1:5

If there are wheels, the box should not be thin it is not practical to make one with wheels to only store a thin plastic box of document.

http://m.staples.com/Vaultz-Locking-Mobile-Wheelie-Chest-Letter-Legal-Black/product_652192

Vicki,

Thanks for your suggestions but none of them met all the requirements.

This item from Jackie is the closest but seems like it would be more likely to be stolen.  
https://www.amazon.com/gp/aw/d/B00DD421X4/ref=mp_s_a_1_4?ie=UTF8&qid=1481558759&sr=8-4&pi=AC_SX236_SY340_FMwebp_QL65&keywords=rolling+box+legal

I like the idea of plastic, with no lock to make it look like "just another file box".  I might have to go leather in order to meet all the criteria but still searching.

Thin
Plastic - lightweight and looks like just another file box
Legal size
on Wheels

Or the one below but the box is bigger.

http://m.staples.com/Storex-Premium-File-Cart-Letter-Black-16-1-4-H-x-15-1-4-W-x-14-D/product_725722

As mentioned in my previous comnent, wheel and thin are contradicting factors that it is unlikely that you can get a thin box with wheels.

Anyway, the leather one is 4 inch narrower in depth when compared with the plastic one.

Post 66 is letter, not legal.  Could work otherwise.

I haven't yet seen a leather one posted.

Something like this might work from a functional standpoint but looks a little too dressed up in my opinion.
https://www.amazon.com/Alpine-Swiss-Rolling-Briefcase-Attache/dp/B008BBOCO0/ref=pd_sbs_236_1?_encoding=UTF8&pd_rd_i=B008BBOCO0&pd_rd_r=M5T4B21Q0C2HM30H4J8E&pd_rd_w=T6nXp&pd_rd_wg=CzZuz&psc=1&refRID=M5T4B21Q0C2HM30H4J8E

It's not totally clear what you want. Can you clarify differences between this and what you want?

https://www.amazon.com/dp/B00304ZM8I?psc=1

Are you more interested in travel/mobile or just movable office storage?