Yacht and Boat Auctions are another good way to find some very interesting Yachts, Cruisers and Project boats to do up as liveaboards. There are a few sites listed below and another good auction site to remember is Ebay. Depending on your country and location, auctions can be a real money saver. People selling their boats at an auction are looking for a quick sale and nearly always willing to accept a much lower than current market valuation.
Project boats in particular are the best source of houseboats, as there are many old and large ex naval or merchant vessels sitting in marinas.