Emerald Bay Housboats and ask for Austin (530) 534-3440. This is their Oroville location number but they just opened a new shop near don pedro that he's at a lot of the time from what i understand. They do amazing things (as evidenced by the 4 story monster on the site) and here's there website
www.emeraldbayhouseboats.com I'm not sure how far they travel but out of all the people who've worked on our houseboat these guys are by far the best and would be a good source to look into.