I'm glad you found one. I also had a hard time finding a gate that wasn't pressure mounted. I have one at the top and bottom of my staircase and since my banister is made of metal I couldn't use pressure ones, they just won't work against my thin banister bars.
I ended up buying one from Babies R Us by Kidco. It's a white steel safety gate that's adjustable (24 1/2" to 43 1/2") and both sides are hardware mounted. It also comes with hardware for installing it to banisters so I mounted one side to the wall and the other side to the banister with the banister hardware. It has a latch on one side that you have to press and lift up to swing open, my 5 year-old hasn't figured how to get it off yet so for me it works great. It wasnt cheap though. $59.99 but I love it because you can remove the gate when you aren't using it (the wall mounts and banister mounts stay in place obviously).
