I recently bought a 2' tall Panache tree from the local hardware store, and it's not looking that great. I did a hasty up-potting from a half gallon to a one gallon, literally put the whole root ball into a larger pot and added some soil. I know, I know, I should have done a better job, but being mid-summer, I didn't want to shock the plant by breaking up the root ball. The problem is that the plant just dropped all it's leaves and started sprouting breba figs. I knocked them off to try encouraging leaves, but no dice, the buds are still clammed up tight. It's almost as if the plant went into dormancy. 

Should I just stick the silly thing in a cool-ish corner and let it sulk for a few weeks?

I live in the San Francisco Bay Area. Right now we're in the third heat wave in two months, today it's hovering around 99*.

I intend on keeping this plant small, no more than 8' high, and potted.

Keep it outside on the patio in relative shade for few weeks at least, until it recovers and show signs of growth.

I hope that you did not expose the roots while up potting, for this might be a death sentence for your plant at this time of the year.

Do not over water and the minute it shows signs of growth increase the amount of sun it gets gradually.

No, the roots were not exposed. It was, quite literally, a lift-and-dump, and new soil was added around the outside. The soil level is the same as original.

I'll move it to the shade, it's in a part-sun spot right now.

Panache is temperamental but it loves heat.  I'd put it in a 5 gal pot and fertilize it.  I'd let it have morning sun so the leaves don't have to adjust later.  With no leaves it won't lose much water.  Make sure the soil drains well.  Sitting in wet goop is what kills most figs.

I had a bad luck with Panache. The first one died and the second one all the leaves drop :(

Well, if I can keep an assortment of Nepenthes (a type of pitcher plant) happy, then by gum, I'm going to keep this one happy, darn it.

By the sound of it, it seems that it's just sulking over being moved from the store to the warmer, sunnier garden, and getting a splash of new soil at the same time. Nepenthes do something similar, where they'll shrivel up their pitchers and stop growing for a while -- weeks to months. I have one that just started growing again after being purchased over six months ago. On the other hand, I have two that I just got that never stopped. Who says plants don't have personalities (or at least preferences)?

Check the temperature of the soil. It may actually be in a stage of summer dormancy. The heat you're describing is very similar to my summer, and most of my trees quite literally stopped growing. After 2 months of experimenting/searching for a solution I found that the soil in my pots were reaching temperatures of 100 degrees or more. Anything above 80 is pushing it because roots can't handle those temperatures. If that's the case, figs will stop growth and eventually go dormant until fall temperatures cool the roots, which will break dormancy. OR you can cool the roots now... wait a week or two and break dormancy yourself. There are many ways to do this, but I suggest top dressing your soil with plenty of mulch and cooling the outside of your container by either mulching around the containers, changing the color of the container to help reflect heat or covering them with something that will provide shade. Frequent watering also helps reduce temperatures.

Keep in mind that soil in containers gets much warmer than the soil in the ground.

Will do! I've had the tree moved under cover for now.

Gradually introduce fertilizer, Foliage Pro and Floralicious plus

U sure those were brebas? panachee usually does not keep brebas anyway, they would have dropped naturally.

Wow a Panache from the hardware store.  I never see any figs or plants ever at my hardware store.......Just hardware.    You luck rabbit.