I didn't find them too rare, they're only in the SHAKING patches, as TTar Trainer said..
It takes a bit of patience but I saw 2 water ones and 1 grass one on my first trip through the forest and I was moving pretty efficiently. Best way to hunt them is with repels, because the shaking patches will still show up, but no wild encounters.
Current status tiiiime!
I just beat the 4th gym, team is as follows~
Shinpora (M) Lv. 35
Zuruggu (F) Lv. 35
Jaroda (M) Lv. 37
Denchura (M) Lv. 36
Hihidaruma (M) Lv. 37
Hihidaruma is now crazy strong now that he's evolved, and he's got Flare Blitz to boot!
I'm liking Denchura, I gave him Volt Change (Electric type special u-turn) and he is a good scouter/lead. He's fast and he can zap things and run before they smoosh him.
Jaroda finally has his special move, coil. It raises Defense, Attack, and Accuracy. It's basically just Bulk Up + Accuracy, but I don't mind. It makes Leaf Blade real powerful.
Zuruggu is still going strong. He's got Hi Jump Kick which has been buffed to 130 base power, so 195 with STAB. He evolves in 4 more levels, very excited for that. ^ ^
Shinpora is still awesome. Taught it TM charge beam, which is nice for flying/water coverage and boosts his SpA up a lot. Running Reflect because it allows him to survive against non-STAB crunches and bites very well and manage to KO the opponent.
Caught some cute deer and mushroom Pokemon and just doing lots of Pokedex filling. I hope to go back and get the water/flying swan soon so I can have it Surf and Fly and not have to take up a slot on Shinpora for Fly since he's special-based.