Could this be trouble?

I am already using a first generation Time Capsule without any problems. I know about the eighteen month failure rate that some have experienced. I am considering getting the Apple Airport Extreme.

Time Capsule is in my bedroom. My plan is to hard wire Time Capsule to the Airport Extreme, which will reside in my living room next to my iMac. Using an Ethernet cable, I will plug my iMac into the Airport Extreme. I have a Roku player in my living room and there are always laptops that are moving around my home. My concern is that the laptops, or any other devices, may bet confused with these two routers. I know about Airport Express but would prefer to spend the money on the Extreme. The Extreme can also be used as a backup router in case Time Capsule meets an untimely demise.

You are buying a very expensive Gigabit switch by using an Airport Extreme in the manner you describe. Here is my contention - if your TC fails - go get another newer TC. In theory these new models should not have the dying in 18 months problem (It may be 36 months, I don't know maybe I'm jaded but I went and got a second TC anyway). But if you have money to throw around you could always use the Airport Extreme as a WDS extender for your TC (or vice versa). So basically it works as you said, as a really expensive Airport Express with 3 extra ports you could hard wire into.

I digress, it shouldn't be any trouble if you setup the AE to extend the TC.

Thanks for the reply. The Airport Extreme has been ordered.