There are many ways to cover hangers but one of the most unique ones I have seen is to cut a pattern the shape of the top part of the hanger & about 6" on the sides, straight across the bottom. Back one piece & front, cut about the bottom of the hanger & add a seam allowance to insert a zipper there. Finish off a section on the top where the hanger will go through. Place right sides together & seam all way around. Leave zipper partly open before doing this so you can get your hand inside to finish unzipping it to turn it. These can go under things seldom worn for hiding places or to put accessories to wear with the garment...Whatever the heart desires.

Family Fun magazine had a pattern a while back and it may be on their website. The made a pattern and sewed 4 sections to cover the hanger. The used strips of quilt atting to give the padded effect.
Susan

Here's a link to some instructions about how to make padded hangers for storing historic clothing or costumes. It's from the National Park Service, and may not be exactly what you are looking for, but the pattern is included and the instructions are very detailed.

Here's a link to instructions for the companion dust covers:

http://www.cr.nps.gov/museum/publications/conserveogram/dustcovers4-15.pdf

CMC

Here is a link that might be useful: National Park Service, padded hanger pattern

I'm a bit of a scavenger and as I have tons of plastic hangers I devised a system for padding and covering them. I think you could easily adapt it to a wired hanger. I would just beef up the part where you wrap the hanger with batting strips. This would give more volume to the part the clothes rest on and should prevent any slipping of the cover.

Here is a link that might be useful: Angie's Whim: Free Fabric Covered Padded Clothes Hanger Pattern & Instructions