Just something to think about. I have a Bunkhouse camper (nearly indentical to the Aspen) and when I asked about putting brakes on it, I was told by them (Bunkhouse people) that although they are available, they don't like to do it because when trailer brakes are applied, they upset the balance of the bike.
As it was explained to me, a motorcycle steers mainly with the front wheel/tire, and the rear tire merely serves to keep the back of the bike from dragging on the ground. When you apply the brakes on a motorcycle, about 75--80% of the braking is done with the front tire due to forward weight transfer during braking. If you have brakes on a trailer being towed by a motorcycle, when you apply the brakes, due to braking action by the trailer brakes, there is a rearward weight transfer and the front tire becomes somewhat unweighted. This serves to reduce the braking effectiveness of the bike, and if you are in a turn, could cause loss of control and possible crash.
Now, I'm not saying that this WILL occur, but it could, and if it's enough of a safety issue for a major motorcycle trailer manufacturer to avoid mounting them, even to recommend NOT putting brakes on a trailer, then it's good enough reason for me to avoid it as well. I guess that may be why you don't see trailer brakes on other makes of motorcycle trailers, either.
I agree that an extra set of brakes could make for more effective braking when pulling a trailer, but the safety issues and concerns just keep me aware that it will take longer to slow the bike down and bring it to a stop.