According to this answer, it is possible, but rarely used.
As for how to get it: I would tend to simply try and order one with the provider of your choice, and enter the IP address instead of a domain during the ordering process.
However, running a site on an IP address to avoid the DNS lookup sounds awfully like unnecessary micro-optimization to me. You will save a few milliseconds at best, and that is per visit, as DNS results are cached on multiple levels.
I don’t think your idea makes sense from an optimization viewpoint.