Also, depending on how literal you were by "basic frame", I highly recommend AndyMark's 2015 Kit-of-Parts (KoP) Drive Chassis as a starting place.
It's what you got if you didn't opt out of the KoP drivetrain. Note that there's a new KoP drivetrain almost every year, so it might be different this year.
You can buy that and get a working drivetrain, OR, you can download the CAD model, use it as a starting place, and design your own custom drive.
If you're customizing their design, it's worth noting that they sell ALL of the kit components separately, so if you're just using the sheet metal from the kit,m you'll save a lot of money buying it individually instead of getting the kit and not using half of it.