I don't know if anybody does this or not,but back when i was running Wizz's Silly Foam tires,this is the procedure i came up with to salvage a little more life out of my expensive tires,other guys have probably got better ways,but this worked for me.If you get to rebuilding the tires before they chunked,the finish is hard to tell from a factory type finish.
Required stuff for rebuilding:

Old Tires (i usually do about 5 or 6 prs of tires at a time)

Dow Corning Flowable Silicone Sealant

Permantex Flowable Windshield Silicone

Old axles

Dremel with a small enough collet to grab old axles

Glass bowl

Laquer Thinner

99% Rubbing Alcohol

220 Grit Wet/Dry Sandpaper

Chunk of Styrofoam

Hair Dryer

Cardboard box

I start by mounting the tires on old axles/drillblanks whatever,something that'll hold the tire in your Dremel and allow you to work with it.
Lightly sand the mounted tires on the piece of 220 sandpaper,using the rubbing alcohol as a lubricant,and your dremel set on a fairly low speed.
After the surface is smoothed out,with a lightly sanded texture,i dip and spin them in more rubbing alcohol to clean them.
Now the hard part,lol.
Take both kinds of flowable silicone,and mix them equally with Laquer thinner in your small mixing bowl,you don't need much of this concoction,just enough to cover the tires when dipped.
The easiest way i found to mix the silicone and laquer thinner is use a mounted tire,and spin the hell out of the mix with your Dremel,there's probably a better medium to mix with then laquer thinner,but i found it to work good for me,and that's what i settled on.
Don't take to long doing this,as the laquer thinner starts to flash off pretty fast,and you want the mixture to be not much thicker then water,at the start of your dipping process.
Immediately start dipping your mounted tires in mix,and slowly spin them in the mix,i use my Dremel set on low for this.
As soon as you you have them completely coated with silicone mix,pull them out and spin the tires on about a medium speed to throw the excess silicone off,this is a bit messy,so do it somewhere where you won't get into trouble with the wife,lol.
As soon as the excess is spun off,stick the axle into your piece of styrofoam facing up,grab another pre-sanded/cleaned tire assembly and do it all over again,after you've dipped the tires all once and stood them up in the strofoam,re-grab the first tire,and re-do the above steps in the now thickening up silicone mix,i always dip them twice,after the second coat,you want to stick the tires into the styrofoam and hang them upside down this time around.Doesn't really matter which way you want to put them at the start,but they have to be hung opposite of the first way,on the second dip
After about 1/2 hour of curing like this,i then take the tires and styrofoam,and put them under a cardboard box facing back up,then take the wifes "old " hairdryer and put it under the cardboard box with the tires.
Then turn hairdryer on,and let it blow across the tires,the hairdryer/box combo should bring the temps up to around 160F to cure the tires.I let them cure like this for a couple of hrs,then pull them out and let them air cure for another 24 hrs or more.
If you want to build up tires that are too small and need to do a couple of coats to get them sized,i do the extra coats,after the 1/2 hr cure and before the hairdryer cure.
This is the technic i came up with for saving myself money on tires,it's a few yrs old now,and there's probably better ways of doing it now,but it worked for me,and saved me a pile of money on silly foam tires,before i switched to slip-ons.
If done right,you won't be able to tell the differance between a factory coating and your coating,except your coating will probably last longer.
We used to do this step even on brand new Wizz Black Pro C's,and the aftermarket coat usually lasted longer then the factory coat.More here in this link
http://www.canho.ca/modules.php?name=Forum...=viewtopic&t=88