I decided to buy him a mobility aid, but after the sticker shock wore off (least I found was over US$300) I decided to make one. There wasn't much available online as far as DIY, but plenty of pictures of commercial models. I decided to make one myself, and this is the result, for around $30 in materials
Dedicated to Merlin, He went back home and got his wings back, 8/10/2009
He was one of those DMK ferrets rescued from a horrid breeder, and we gave him the best life we could for his entire stay with us. We miss you bud.
Step 1: Materials
$3 - 2 Clothes Line Wheels (Lowe's, Hardware, near nuts and bolts)
$5 - 3 foot perforated angle metal bar (Lowe's, Hardware, near nuts and bolts)
$6 - 500 Piece Plastic Wire Ties, aka Zip-Ties (WalMart, Automotive) - Won't use them all)
$3 - 6 piece wooden craft boards (WalMart, Craft Section)
$1 - Bandanna (WalMart, near purses and such)
$2 - Hook & Loop Tape, aka Velcro (WalMart, hardware)
$7 - Pair of Shin guards, soccer player type (WalMart, Sporting Goods)
(Lots of other stuff in the picture that I ended up not using. Your design may vary). If you look online, you may see why some of the extra stuff was bought but not used.
When shopping, keep in mind how long your animal's body is. You want a "cradle" that will support their body in a way fitting the injury. Sometimes you may want to support them by the legs or hips by means of a harness setup.
In our case, we needed to support Merlin's torso, because of an irritation with his legs that made us want to minimize contact there. If you need to support them by the legs or hips, you may want to use a different cradling method.
We chose the smallest shin guards we could find. You may want different materials depending on your particular needs. Be creative.