I make my quilts "comforter" size - mainly because we use quilts for blankets (we don't own a store-bought blanket of any kind)..... back in the day, when central heat was not available to most (any) people, quilts were made huge to cover beds and bodies, with a 'drape' to keep cold drafts out - and they were HEAVY, especially when you got enough of them on the bed to stay warm at night!
I have made bigger quilts - but the size I can quilt on my Lil' Gracie II frame is under 98 inches (it says 98 inches but you can't really go that wide)...
If you are making the quilt for yourself - hey - may it ANY SIZE you want... there are no rules... and no quilt police!