IIRC, I made riding crops until ~365, but they grey out at 370. The key with using riding crops to skill up is patience and the AH.
If there are others selling it, wait until your underbidding price will net you at least your cost. This can take several weeks.
At around 365, I decided to the barrel through to 375. I made a dozen Heavy Clefthide Boots and disenchanted them into Large Prismatic Shard. Factoring out the value of the shards, I lost ~60g on each boot so it cost me ~720g to get that last 10 skill.
On the unlikely chance that you're exalted with either The Sha'tar or the Keepers of Time, you could make Drums of Battle or Panic...