Custom-made cat tree houses are available for sale. They are hand-made from wood and carpet - not cardboard or plastic like ones common at pet stores.
They are available in two-tiered and three-tiered designs (see pictures and flyer for more information). Additional customization (e.g. a single-tier, or no ladder) is possible - just ask. Each is built sturdy to last!
The inside of each tier is about 12" x 20" - holds both large and small cats comfortably.
The base of each tree house is 20" wide and 30" deep.
Two-tiered designs are about 34" tall and come in two varieties: two posts ($60) and three posts ($65).
Three-tiered designs are about 54" tall and are $85.
Carpet colors vary, but are all neutral tones. It could even be made to match your own carpet (if you supply it) at no additional charge.