You can get the frameset, but it's 4000 Euros and I already run a Lefty fork on the borked frame so getting another one seems too profligate even for me.
All a bit mute because cannondale have little interest in selling frame / fork only; the full bike can be had for < £4k. Think I paid about £1,600 for mine.
Cannondale F-Si is still QR.
Bosh. Job Done.
If you can actually get frame/fork only. You'd need the 'fork' because it runs a large offset to, uh, offset the slack head angle.