My two are both alu.
One a Giant Bowery 72, with front and rear brakes on drop bars. This was a "cheap" bike in 2008 ish, but nearly component apart from the frame has been upgraded.
The other a Nelson track frame, for TT's, set up with low-pro TT bars (aka bull horns) and a single front bar end TT lever. Only needs one brake for a fixed.
Also bought this one about 10 years ago, but is onle ridden for about 10 time trials each year, so less than 200 miles a season.
As I said, but are alu. I would love to get a carbon fixed frame, but they are outside my budget and all the nice ones are dedicated track framesets, with no provision for a front brake. I would have to buy the frameset and a set of TT forks to make it rideable for TT's and it just pushes it out of my budget.
I don't really understand why manufacturers don't offer framesets which are drilled for a front brake. Even track specialists would have reason to try out ther bikes out on the road or after track usage, convert to a road fixed or SS.