I might be ignorant to some of the smaller, modern kits, but a few things come to mind if you want to make something to your liking:
1. I would be worried about a boil off rate on something that small. Any drastic change in weather conditions would wreak havoc with your OG. I figured out boil off rates for my 5-gallon batches, but I'm still working on the efficiency as I don't mill my own grain yet.
2. Yeast. Most of the homebrew shops sell yeast for 5-gallon batches, not 1. Double pitching works, but 5X?
3. Are you going to use tablets and bottle directly from the fermenter? With something that small, I'm not sure using priming sugar and bottling from a bucket is going to work that well. The spicket is usually around the 1/2 gallon mark on a bottling bucket.
4. Is something that small (if not an all in one) going to hold mash temperatures well enough for an hour?
5. Will something that small ferment without drastic temperature changes?
I did notice a BIG difference going all grain, but I also bought a 15-gallon kettle for the full volume I need with BIIB, a propane stove for outside (which I can use outside about 11 or more months out of the year here), and a refrigerator with a controller.
If you want to go bigger, BIIB is about the easiest thing outside of an all in one.