I am sorry but I am not familiar with the Slicehost API.

Since no one asked, I haven't really truly considered Slicehost an option for my projects. When I started researching the various options, Linode looked 2nd best by the numbers for VPS. prgmr.com looks the best but I am not sure I'd bet the farm on such a tiny operation. Slicehost is of course similar to Linode but it seems Linode gives you more bang for your buck and has nothing to do with Rackspace which in my limited foray into this hosting world seems like a good thing (but what do I know?).