The force ($2k retail) has been the go to performance IK. Its not going to let you haul your dog around though unless its a little lap dog.
The lynx ($1600) is the next best thing performance wise from AIRE. Its made to haul some weight but not sacrifice all performance and is probably my favorite IK as an all around boat. I like it because you can move it around quickly empty, you don't have to get soaked by every little wave if you don't want to and it can haul some shit.
AIRE Outfitter is the most stable, biggest tubes, not what you are after.
The Trib tomcat ($700) seems to paddle almost like the lynx performance wise. It is a good all around boat, especially for the price. If you want to keep on a budget, it may be the answer.
Another option for a sportier ride and a smaller woman may be the Tributary SPUD ($420). It is made as a kids boat but I bet you'd be in the weight limits assuming your dog isn't 100lbs. I think you could really move it around. Its not quite as tough material as any of the others.
The RMR Animas ($1k) is a bit sportier and less stable than the lynx (very tapered tubes), comes with thigh straps and does not use the bladder system which you may or may not like. I only paddled the prototype that had too thin of a floor so I was sitting in water, which is my first thumbs down on a ducky, but that has changed. It may just be the ticket for 125# and a dog if you wanna lean on the sportier side but the SPUD is too small.
I think RMR is coming out with a new IK this year so you may wait it out. The pic I saw looked like it was sportier yet. Maybe I wasn't supposed to talk about it yet.
Another option is to hit the classifieds on here or go to some of the spring swaps like Raftopia at DRE (first weekend in April this year I think) and see whats there. People seem to get rid of duckies pretty often and you can snag a good deal. They are wet and miserable, but you like that! They also have most of the boats I mentioned and you could look them over.
Im not sure what Wet Dreams in GJ has ducky wise or what is available in GS to go look at and see for yourself. You know what a sporty unstable kayak looks like compared to a more stable one. Look at a few duckies and you'll get the idea. There are definitely rentals out there from some of the outfitters. I wanna say Wet Dreams rents.
Thigh straps and foot pegs can be added to any IK.