Do they make tri bikes with clip-on aero bars?

There are some low-end tri bikes that are set up with drops and STI shifters. The QR Trueno is one, for instance. BUt once you get past that level, they're almost exclusively set up with bar-end shifters. It is possible that a shop might be willing to swap out for a traditional cockpit, but you might have to pay a bit extra.

http://www.rooworld.com/bikes/2006/trueno.aspx

I am hearing you sister; I had the same concerns when I switched to bar end shifters on my tri-bike  from the 105's on my road bike.  Now that I have logged some miles on the tri-bike, though, I really like the ease in the shifting of gears, especially while in aero, more than the 105's on my road bike.

Humble opinion is that if you are going to take the plunge for a new bike with tri geometry, you might want to consider going with the full bar end shifters.  If you are going to be on the aero bars, you might as well make it easy to shift (which you do more frequently than brake) ... and regardless of where the shifter are (bar end or on the drops) your brake is going to be in exactly the same place.

Just 2 psi's worth from the peanut gallery ...

Alternatively, put your brakes where your shifters are:

http://www.hedcycling.com/aerobars/thirdbrake.php

You'll have to get over this fear if you want any kind of aerobars on any bike.

That’s exactly what I was thinking. Unless you have shifters/breaks on both: drops and aerobars you'll always have to switch from one to another to break no?

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See my previous post above.

 When I finally get my new tri bike I was considering swaping the front brake lever for the front shifter.  So on the aero bars I'd have control over the front brake and the rear derr, while on the wings I'd have the rear brake and front derr.  My reasoning was that the front brake and front derr are the two controls I use the most.  I never touch my rear brake, except when coming to a stop (I'd be out of the bars anyway) and I don't shift the front enough to need that control on the aerobars.  That set up should let me stay aero almost the entire race, including managing tight turns at high speed.

Now I see this third brake, I might have to investigate, altho the weight weenie in me is saying to stick to my origional plan.

it's all about weight transfer.  When you brake, your weight shifts forward.  This allows the back to break free MUCH sooner.  Just set your bike on the carpet, grab the back brake and try to scoot it forward.  Now do it with the front brake.  Which one can you do?

The front brake will give you the maximum controled stopping power with the least chance of breaking free, unless it's wet or slippery.  Going over the bars comes with poor bike handling skills, when you don't anticipate the force of stopping and fail to brace against it properly.  If the rear brake had the same stopping power as the front brake, you would be just as voulnerable to going over using it.  So if you are coming hot into a corner and need to scrub speed quickly and you grab your rear, either your wheel will lock making you skid, or you won't be able to scrub the speed as fast because you are not letting it skid.  Where as if you grab the front and keep your weight back and centered, you can slow down in a major hurry.  In fact, I'm willing to bet that you don't have the hand strength to make your front wheel skid on dry pavement.  Also remember that the quicker you stop, the more momentum is being transfered, which means the more force on the front wheel.  That force is transmitted not only foreward, but down.  So the quicker you stop, the more force is driving the front wheel into the ground, improving it's grip.  You may have 100 lbs of body weight on the rear wheel, but when stopping hard, you can get double that or greater on the front.    If you learn to use the front brake as a primary, you will have much more control on fast descents through corners and become a much more confident rider. 

This is why crit riders use almost all front brake and why race cars are tuned to have their front brakes engage stronger the rears.