I have several commercial/industrial steel shelves. These are 11' tall so you must have the height to use them. Widths are 24", 36", and 48". Lengths 8' and 6'. These are steel (end pieces, horizontal pieces, and supports and use plywood as the shelving surface.
Most are currently assembled and in use, but currently have available for sale one 48" unit with horizontal pieces in either 6' or 8' lengths.
Remaining assembled portions may be available soon if you're not in a hurry. These are very heavy duty shelves - not the stuff they sell at the big box stores.
do NOT contact me with unsolicited services or offers