I'd be scary on a light carbon road bike,....all my road bikes are steel and heavy, but fairly comfy considering there unforgiving geometry.
I passed a guy on a carbon road bike today who had stopped, I'd completely forgot about him until about 5 miles later he passed me saying, blimey you took some catching up! I'd hazard a guess my bike cost about 2500 pounds less, weighs twice as much as his,.... mine also looks sexier and gets more admiring glances because it's retro and all these carbon ones look pretty much the same.... then again he'd probably done 100k and i'd just set out from work to come home!
My mtb is carbon though!
why not consider a nice custom steel bike, trick it out and you'll have something completely unique to you, it will be comfortable and if it breaks it can be fixed, it will never die.*
*don't quote me on that.