You can check out these guys (Click here
) as they are not only mobile, they will come to you, but also work on both house and chassis issues. The couple we talked to that used them said their charges are rather high but typical for mobile services. I haven't used them personally so I can't speak first-hand as to the quality of their work.
ETA: I just noticed that they do have one review over at the RV Service Reviews
website and that party rates them "excellent" in both the value and quality categories ...click here
for the review.