Superpredator - I'll go out on a limb here and say that I would be inclined to bet that the Aria's DAC is in fact better sounding than the Revolution's sound quality. Now, before anyone jumps on me I will say that, yes, that is unfounded speculation and I probably have no right to say that. However, I do have a Revo 7.1 I use for coaxial digital output to my outboard DAC but have listened to it's analog output and while it's pretty decent it's nothing stellar and I am sure many here would agree and others would argue there are a lot better sounding cards. So, if in fact the Aria's DAC is better sounding than your Revo's output then all you will need in the end is a USB cable going from the computer to your Aria and it's end of story - sell your Revo unless you use the 7.1 features.
If you get an Aria and decide that the Revo still sounds better I wouldn't worry so much about using an adapter with the Revo's mini analog output to the Aria. If you are that concerned about a mini to RCA adapter degarding the sound then buy a high quality mini to RCA cable, there's a lot of them out there and many people make excellent ones here on Head-Fi. This isn't an adapter I'm talking about, I'm talking about a RCA to mini built cable.
Hope that helps.