I filed a 7004 for an extension to file my business return today. Can I file it electronically through Turbotax by midnight tonight?
The due date to file an extension for your business tax return has long gone. The last date to file the extended tax return is typically the 15th of September, whereas the last date to file your personal tax return is the 15th of October.
So in short, you can't extend today the submission of your business tax return. If you had an extension in effect you could submit your final one before midnight today. If you were not ready - you could submit what you have electronically (through the Business TT, if you have it) and finish the final version in the near future - you could then submit the final version as an amended return.