I'm just a front-derailleur short from finishing the Stumpjumper (I needed a down-pull, the one I had in house was top-pull...) but I'm already starting the next challenge.
I own a very nice triathlon bike, a titanium framed Guru Tri-Ti, but I don't use it enough. Most of the time I'm on my mountain-bike(s) or on my 'normal' road bike (a steel Pegoretti), I just take the Tri-Ti for a couple of races a year (and ride it a couple of times before each race).
What I was thinking: since the Tri-Ti is soooo nice (I belong to the generation that considered titanium 'the magic metal'), I could fit a normal dropbar + clip-ons (+ right-lengh-stem and different brake levers) and use it for normal road-racing and tri (removing or not the clip-on aerobar). I'd then keep the Pegoretti for training and the lighter Guru for racing.

I'm already measuring and testing different solutions (stems/handlebars/seat positions), including mixing and matching different brand transmission parts.
Regarding "Mix 'n match": I know it's not recommended, I know parts from the same brand are carefully engineered to work well together but then... who cares, if I manage to use Campy levers with Dura-Ace derailleurs? I do it at my own risk, and on my own bike.
The fact is, the bike is equipped with a complete Dura-Ace 7800 group, with bar-end shifters. Looking for a brake lever/shifter combo, I've decided to avoid externally routed cables (DA 7800 or other lower-level Shimano shifters), but I also don't want to buy necessarily the DA 7900.
Campy Record 10v shifters are relatively cheap these days (with the arrival of Super Record 11v...), and they are top of my buying list. I've seen a trick to use Campy shifters with DA derailleurs, using a different cable routing. A couple of old Chorus 10sp shifters I have around will allow me to check this solution out before I buy.
And then, if this doesn't work, DA 7900 will be my second -and sure- choice.