I got an email from Microsoft about new SQL Server version ,"Denali" CTP3, is released. I read their documents it got more support features in cloud. Moreover, its express version is more focus on localDB. This sounds like a in-process DB. That is very similar with sqlite. I have a look on that to how much improvements they have.

Click here to download from Microsoft

Reference:
SQL Server Code Name "Denali" Cloud On Your Terms
SQL Express