Custom HO design companies?

[Big Sol]

I was wondering if there are any companies out there that are in the business of producing custom rolling stock and locomotives for private parties?

For example, if I were to send in a logo and a basic color scheme for a G-Series locomotive, the company would already have a blank locomotive ready, they'd paint it to match my color scheme, then paint my logo on it, and then mail it to me. Obviously, there'd be a steep price...cost of the loco itself plus the paintjob, which would mostly be handled by a computer or machine anyway.

Same for rolling stock. Wondering if anyone out there knows of such a company.

[SteamGene]

There are plenty of custom painters for locomotives.  Check any model railroading magazine and you'll find plenty.  You can probably find quite a few if you contact your local NMRA division.   There are also makers of custom railroad decals - Rail Graphics is one. 
If you have a large car order,  Accurail will decorate cars, as will Bowser and a few other companies in HO.
By "G-series," do you mean G Scale? 
Gene

[Big Sol]

Sorry, I meant GP-Series....

[Jake]

Yes, as gene said there are plenty of them. Like athearn for example.

[jayl1]

Bowser will, as mentioned,  do special runs.  However they have a rather large minimum order.

There are also companies that make special run decals so you can paint & decal your own equipment.

[Paul M.]

Athearn'll also paint them , but again, they have a big minimum order.

[r.cprmier]

There is a guy or two on this forum who will possibly do it for you.  Check the forum for pics of their efforts.  I am sure you will agree, they are very good!
Rich