SQL Server xp_cmdshell: account's access changed - how to avoid restarting the service?
Depending on how secure you want to make it (Not dwelling on it as you've requested), a proxy account could be setup for xp_cmdshell operations so that it does has local admin.
xp_cmdshell_proxy
Since you're interacting with the OS at this point, you could also create scripts to switch execution context to another user either through powershell or through the normal command line.
Obviously this all depends on who has access to SQL Server and Agent, and if it would be an issue. Only you can answer that.