What you are looking for is Octopus joubini. There seem to be fewer species of octopus being sold in the US this year than in previous years. Perhaps the availability of tank-bred bimacs has made some local fish stores reluctant to carry other species. I don't know where you could find this species right now.
Everyone: we have a lot of requests for pygmy octos such as O. joubini. Also larger octos such as O. vulgaris. Please let us know if you see these for sale.
Yes, TBSaltwater has two species of octopus on its order form - but one person called them this week, and they hadn't had a vulgaris for a long time. The site that says they will catch them for you hasn't been updated in a while.
And yes, everyone agrees they have wonderful live rock! But not cheap!
Tampa Bay usually has Octopus mercatoris, not O. joubini. Actually that is good because O. mercatoris is a big egg species while O. joubini is a small egg species. That means that O. mercatoris does not have a planktonic stage and there is some hope or rearing hatchlings. Almost all references to Florida O. joubini are in fact O. mercatoris. March is when the most females are brooding, so it is a good time to get them if you want eggs and hatchlings although the adults will not be long for this world.
I currently have some O. mercatoris hatchings and they are doing well. During the day I never see them, but around dusk I had adult brine and amphipods to their tank. When I check later in the evening, the juveniles are up on the glass and I occasionally catch one feeding. They are cannibalistic, so don't expect to rear more than a few per tank.