I need some plans for a 15x20 Shed. ( 15 Wide 20 long )?

I need the shed to keep 3 3 Wheelers ( 2 Honda ATC 200x's And Honda ATC 250sx And 2 Dirt bike KX 125 and a KX 80 ) I also need to have enough room for a Tool Box and needs to be tall enough for extra storage space under the roof in the form of a small loft for engines and other junk. Would Perfer Metal Roof and a Wooden Frame. Would like it to be a little bit off ground but not much.
Give me whatever you got so can bounce ideas off of it. Thanks!

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