Q1 : As far as I have understand, current version of XNA Build isn't the final one. When it will be released, approximately at least
Q2 : I haven't found any mentions about version control systems (even SourceSafe) exploring MC2 XNA-sample, maybe I was inattentive. In what manner it will be possible to incorporate a VCS into XNA
Thank you.

Questions about release date and VCS
StallionLZ
Q1 : Will you add VCS support for assets and xnaproj-file in Visual Studio
Q2 : If yes, will it be customizable or strictly bound to SS or Team Foundation Server
Thank you.
Antony Kancidrowski
Q1: Correct, what is released now is the March 2006 Community Technology Preview of XNA Build. We currently have not released schedule at this point on any level of granularity. We’re still very much in the process of collecting feedback from this CTP so if you have suggestions let us know!
Q2: Your correct, the MechCommander 2 sample does not do anything with source control. You certainly could integrate it as necessary to almost any source control system that has a command line interface using the Exec task (Which issues command line commands) or using MSBuild tasks that work with source control systems like those available for Team Foundation Server.
If you have any more follow up questions, let me know!
Modian