I've heard getting married to a Lao person in Laos is very difficult and expensive and not many people attempt it. Not sure how much the costs are or how long it actually takes though. Also, you're not meant to have sex with a Lao national before marriage, so this could prove problematic for many foreigners.
Do people usually marry their Lao partner in Thailand, or another country? Will the marriage be recognised in Laos?
"Permission for marriage or engagement to a Lao citizen must be submitted in a formal application to Lao authorities. Penalties for failing to register a relationship range from USD$ 500-5,000, and possibly imprisonment or deportation."