I too became tired of trying to fill them with the engine running.
http://www.amazon.com/gp/product/B00...E4HCBXUMEETI2U
There is a thread on this. A mount is available so I placed mine in a small little used compartment. Lengthening the power cable a few feet is fine. If I need to use it somewhere else it is held in place with wing nuts.
This is not a cheap unit as compressors go. Those cheap compressors I have found seem to have the same junk regulator just waiting to fall apart. As boy toys go this is not cheap but sure does the job well. Not a speed demon but this model can run as long as it needs to. The accessories are well built.