Currently there isn't. I've got one that sort of worked, but has been designed for 1.0, so chances are it doesn't work anymore with the latest code.
Implementing it is not easy due to the current DB driver and Query Builder architecture, which uses a generic SQL compiler that requires an ANSI compliant backend (which MSSQL is not).
This is why for 2.0 we're going to redesign the entire DB layer, so we can have platform drivers with compilers per driver, which will generate code specific for the platform. You could even have a driver for CSV files and access it through ORM if that would tickly your fancy...