I have one 'big' rocket that I have been actively developing; Krazed.
I got hooked in model rocketry in about 1995, when my father dug out his box of 20 year old rockets, and took us out to launch them in the desert. Only about 1/2 of them came back in a repairable state, but none the less I was addicted.
Of course the small rockets got boring after a while, so come Christmas time an Aerotech Barracuda and Initiator came, which got us started in MPR. Then my dad got his level 1 Tripoli certification on a recently acquired PML Bullpuppy. Of course that meant that we could buy motors big enough to send that poor Bullpuppy a few miles up, so it was time for a bigger rocket.
This started the Krazed trilogy, which began with a PML Amram 4 painted lime green. Of course that rocket was large enough that it would fly well on a J or K motor, which meant that it was time to get a level 2 certification (what a perfect cycle...). We also wanted to be able to fly it on hybrid motors (the ATFE's regulations were starting to become a problem at this point in time) so we decided to add in PML's CPR3k dual deployment system, and stretch the bottom to allow for a 36" long hybrid motor. We had an unexpected discovery while painting him, which created a very unique 'desert playa' crazed paint job--which is also where he got the name Crazed I.
He flew beautifully for a number of flights, and we decided it was time for a hybrid motor. We had originally planned to use Aerotech's system, but they stopped manufacturing it when their Nevada plant burned down. So we decided to go for a West Coast Hybrids motor instead. Unfortunately, our alternate ignition system didn't work as planned, which caused the motor to over pressurize, and explode the bottom half of the rocket.
Thus was born Crazed II, which was the top half of Crazed 1 (complete with all of the electronics, parachutes, etc) on a new fin section that was a replica of Crazed I.
Crazed II flew beautifully, topping out at just over a mile high on a J540-R. It actually was almost too perfect, it Just Worked. So to bring some chaos into the launches, I started the GPS Tracker saga. We also got a Hypertech hybrid motor to help bring the launch costs down, and avoid the ever increasing ATFE's restrictions. Sadly, Crazed II met his demise when we had some electronics related problems (most likely the electronics never got armed...) and came back down ballistic at just over 200mph, which obliterated the airframe, and all of the electronics--including my GPS tracker.
This lead to the creation of Krazed III. Since we were rebuilding the rocket from scratch, we decided to slim the airframe down from a 4" to 2.1" to reduce weight/drag, but still allow it to fly on the same motors as Crazed I and II. We also hoped for some flights exceeding mach, so the airframe was made entirely of Hawk Mountain's fiberglass tube. It was also decided that it was time for a new color scheme (yellow in white did not stand out too well in the desert), so it was changed to blue on purple. The name changed from Crazed to Krazed to match the name that I put on all of my projects/products, Krazer. Unfortunately, the GPS tracker still wasn't quite working, and on a launch on 4-6-08 we lost him, and now he is laying out in the Mojave somewhere
So now I am working on developing Krazed IV. My current plan is to steel the airframe from another rocket we have that is essentially the same as krazed III was, but is only 1.5" in diameter. Unfortunately I will not be able to fly the big 54mm motors, but it will keep the launch costs down and hopefully let me get all of the bugs worked out of the next revision of the GPS tracker.