Dual-SIM adapters have been available for the iPhone for a while. It’s even speculated that we could see dual-SIM technology show up in the iPhone 5. If none of the current offerings for dual-SIM adapters appeal to you, you might want to see what Rebel Simcard has cooked up.

The Rebel 2Phone case for the iPhone 4 will give your device the ability to make and receive phone calls on 2 different lines, or 2 different carriers. The coolest part is that both SIMs are active at the same time, meaning you can make calls on both lines simultaneously…

The case is actually an all-in-one accessory with multiple purposes. It has a SIM card slot built into the inside of the back cover that connects to your iPhone via the charging port. This is a major improvement over previous dual-SIM designs, which commonly has the second SIM card dangling alongside the outside of the device.

That’s not all, the 2Phone case also contains a rechargeable battery that powers the dual SIM operation. Not only does it not drain your iPhone battery when making calls on the 2nd SIM card, it will actually recharge your iPhone if your battery gets low.

It is important to note that the case will only work with jailbroken devices. Their 2Phone app that allows phone calls on the 2nd SIM card obviously didn’t meet App Store requirements.

The entire invention is housed in an attractive case that seems to be easy to get on and off. The device is currently available from Rebel’s website and will run you approximately $250.

This would be great for someone looking to have multiple lines on their iPhone. You could also instantly switch to a different carrier when service on your main carrier gets shoddy. Although I couldn’t justify a $250 accessory like this and 2 phone bills, the product is certainly innovative.

What do you think? Would you order one of these?