The most important thing of this exrcise for me wasnt the final look but all the learning about rig.
It has some things i could correct, like the head bounce, the time span in wich the front legs touch the ground, and the tail bounce. Any other things you think it could be better please say : )
I used a lot of follower modifier (LightWave) to; make joint bones strecht and maintain the joint thickness; animate one paw's IK target and the other would follow with some delay; make the tip of the tail curl more when the parent bone curled a bit.
Altough the weight maps would be different i might try to make a more dressed up model and see if i can simply replace the low poly.