Nordost Blue Heaven
They sell them in standard lengths up to 23ft.
Obviously these cannot be shortened by the end-user and I am pretty sure Nordost doesn't offer this as a service. I have Purple Flare's which I'm now using for my AV system and they are a few feet too long. My issue with the length (and this design in general) is inflexibility of the ribbon which makes cable management difficult. I'll get rid of them eventually.
If you are OK with the extra length aesthetically, then I'd say leave them as is.