What you mean by "SSD" USB drives? While "flash" or "thumb" drives use similar memory technologies as SSDs, they are not the same thing. SSDs are used for mass and permanent storage. Thumb drives are typically used for smaller storage needs and should only be used for temporary storage.
If you really meant a thumb drive but are concerned about space, you can always use a USB extension cable between your USB port and the thumb drive. I have seen them as short as 6 inches up to many feet.