Hi,
How is the architecture of your local SharePoint site? Instead of uploading manually the sandbox solution, you can automatize through PowerShell cmdlets in a script.
Regards
------------------------------------------------------------
Juan Carlos González Martín MVP de SharePoint Server
Director revista CompartiMOSS: http://www.gavd.net/servers/compartimoss/compartimoss_main.aspx
Blog: http://geeks.ms/blogs/ciin
Twitter: @jcgm1978
------------------------------------------------------------