It seems that Valve is preparing to launch four versions of the Steam Machine. According to Tweak Town, code in the latest Steam update hints that four distinct models are coming.
These four Steam Machine models don't have names yet, but they could include 512GB and 2TB storage variants, which could mean a Steam Machine bundle with and without a Steam Controller. Valve has confirmed, that they intend to release at least two variants.
Valve has a new reservation system in place, and it's similar to the Steam Controller, which sold out in minutes. The reservation system is already active on Steam, and hopefully we get an official announcement in May. Pricing is still a mystery.
The Steam Machine is still supposed to come out sometime during 2026.