I was about to write a small fan-fic fight for this but gave up mid-way X_X
But I still think that Sasuke would win, even if it's not low difficulty or anything. I'm thinking more on the lines of:
1. A quick sword battle between Sasuke's Katana and Kimimaro's bone sword, where both match each other until Sasuke uses Chidori fused with his sword to cut through the bone sword. He catches Kimimaro by surprise but is blocked from dealing a killing blow by bones spawning from Kimimaro's arm.
2. Sasuke retreats and uses a Katon, which Kimimaro is shown to shrug off while using CM lvl 1 to cover his body with bone armor.
3. Seeing this, Sasuke tries using a genjutsu, but finds out that Kimimaro can break it by causing himself pain through using his bones. He surprises Sasuke by throwing some of his bone finger bullets at Sasuke, yet fails due to the Sharingan's natural precognition.
4. Kimimaro goes for another close combat fight with Sasuke using a more diverse fighting style, complete with several bones flying out and looking for a good hit. Into the fight though, Sasuke uses Chidori Nagashi and stuns Kimimaro temporarily.
5. Sasuke tries going for the final blow, but is stopped prematurely by a bone spike coming from the ground. He soon realizes that more and more are emerging, and is forced to use Lvl 2 of the Curse Mark and fly in the air.
6. When the bone forest is made, Sasuke finds out that he is unable to find him even with the Sharingan, and assumes that it was a suicidal move. He is proved wrong however, when Kimimaro appears from a bone besides him and blind-sides Sasuke in air. Sasuke only has time to turn around when he is impaled with the bone drill.
7. Kimimaro thinks that he's won, but Sasuke uses Oral Rebirth and finally gets a good hit on Kimimaro using a Chidori. (Kimimaro is slower in Lvl2 than base, and is fused with his bone now while under a surprise attack).
It might not be the best scenario (and there are hundreds of others) but I think Kishi meant to put Sasuke above Kimimaro (at least after the Time Skip, w/ Orochimaru absorbed)