This is what i found on a similar style of metal desk,

brand the desk is. It reminds me of a Malibu.”
“older gray desk for a sewing surface. These type of desks were often used in government offices. They are super sturdy, but weigh a ton.”
“Office desk is inexpensive and large”
“extra bedroom used as seeing room, Ben's desk?”
“desk as sewing table drawers for notions at fingertips”
“great set up using old desk”
“My sewing desk in my studio.”

it's a vintage tanker desk

http://www.americanlisted.com/california_5/furniture_23/vintage_mcdowell_craig_steel_tanker_desk_375_santa_maria_ca_14472066.html you can find them quite readily as vintage furniture and then if necessary have it dip stripped back to the raw metal for the look in your picture.