There is good reason to focus on entrance-way reinforcement because 75% of all burglars enter through the door. Here are a few more ideas I found:
The Door Club $25
I have a feeling the usefulness of this item would depend upon how well its installed. Even if it is installed well, I dont think it would stop someone who is determined from bringing down the door, but I do think it would add at least several seconds to the breakdown time.
Another version of a similar device
Door Frame Reinforcement kicks with upgraded door jamb and longer screws-
There are quite a few of these kits on the internet and at retail stores like Home Depot. Again, I dont think these kits will stop someone who is determined, but will add several seconds to breakdown time.
The best way to secure an entryway in my opinion is through one of these security screen doors with a locking deadbolt. These are typically swing out designs so there is no way to kick it down. You could probably pry it open, but not kick it. I think this security screen would add minutes to breakdown time. If you combine all the tricks together such as security screen, door jamb reinforcement, door club and finally the door knob alarm then it would add several minutes to breakdown time.
At this point, the burglar would probably try an alternate method such as breaking through a window. However, breaking a window is messy and dangerous. Ever try to crawl through a broken window and then there is the noise it makes plus it really looks like you are trying to break into the house.
The preferred method of burglars is through the door.