Hi, I'm professional c# developer, and I can do this application.
I could create simple WPF application, where you would log-in with your primary twitter account, and will create list of accounts for "re-tweeting". Then application according to the specified settings (5 recent, 10 recent, etc) will retweet with random/one-by-one account.
Application will show you progress as well.
Additional functionality could be added
Best regards, Anton