Jetrench, love that last pic.

Tannerlb, I've flown formation with a couple of friends.

With one friend, we were flying nearly identical Dynaflite 40 sized mustangs (I built them both side by side, mixing the wood to normalize the weights, etc).
With the other friend, I was flying the mustang, and he was flying a Midwest 40 sized 109. We also flew formation with small aerobatic slope soarers.

The KEY to success was that we were very familiar with each other's flying styles/habbits. Of course you also need to be thouroughly familiar with your models flight capabilites, especially at the low end. One pilot is lead (that's the easy part) the other pilot flies as the wingman (that's the hard part).

When it was good, we were able to complete several circuits around the field in formation (model separation ranging from 3 feet to 6 feet) including mild aerobatics (aileron/axial rolls, half rolls to inverted). We also did formation takeoffs and landings

Some tips:

For the lead:
Fly smooth and predictably and consistantly (scale-like).
Throttle set at 60 to 75%
Calls out manuvers
Does NOT try to hold formation together (beyond flying smoothly)

For the wingman:
Controls model separation via throttle settings and subtle manuvering
Easiest place to close or increase separation is during the formation turn by flying slightly outside or inside the turn.

Sorry, no pics of the formations, but you can see the mustangs that we flew formation with here:
http://www.elliotfan.com/temp/p51.html

and the slope soarers here (midjet and obelix)
http://www.elliotfan.com/temp/slope.html

Regards,
-E