I don't feel that you have to sacrifice strength/power development for conditioning at all. I think that it's more advantageous to focus on one or the other, so that more dramatic gains can be had in a shorter amount of time, rather than more mediocre gains across the board in the same time span. It also depends on the trainee him/herself, and what their needs are. Time isn't the only factor when considering adding S&C training to your schedule - you have to look at fatigue, recovery ability, as well as just plain burnout. This not only considers physical variables, but mental, emotional, and nervous variables as well.
You have to make sure your body can physically recover, we all know that. However, just b/c you're doing a short (and highly intense) routine (be it strength/power or conditioning) that you've found your body can recover from, doesn't mean your nervous system can. That's the catch 22 with many forms of S&C training - intensity and duration are inversely proportional. Shorter workouts are more intense, and might be easier to recover from physically, but take more out of your nervous system. Longer workouts, by nature, can't be as intense, and are therefore easier on the nervous system, however, they can be much more demanding physically. You need to find a good balance between both - esp. considering that you have to add the rigors of your skills training to the mix.
You also have to consider motivation. For most of us, this (mma, S&C, etc.) is more hobby than it is profession - you don't want to get to a point that you're dreading a workout, or that you just don't want to train. Training should be hard, but enjoyable (if that makes sense).
A lot of this is why I'm putting together the expansion pack based around 2-day workouts. While I was in the Middle East, I found that I experience much of the same sorts of challenges. It wasn't b/c skills training was taking a toll on me, but b/c the environment just sucked. We worked 7 days/week, 84+ hours/week. If you went a couple nights not sleeping good, or had to put in some extra hours, or spent time during the night in the bunker from IDF (instead of sleeping in bed), it could take it's toll on you - mentally and physically. I found that I might have stretches in which I could make all my workouts in a given week for a month, then I'd have a hard time getting just 2 workouts/week in. I found that if I put together 2-day programs the way I was, it allowed me to train pretty much when I could/wanted to, and if I had to skip some days, I could easily pick back up where I left off w/o having lost workouts, or having a jacked up schedule.
ANYWAY - back to SS's question, I'd focus on power/strength (do some basic strength work to keep strength up, while applying speed components to increase power), while doing a maintenance level for cardiovascular/muscular conditioning, since you're getting most of what you need for this in your rolling. Focus on what will make you better on the mat.