Check out GamersGate (operated by Paradox Interactive). They sell a wide variety of games, including many recent releases and all Paradox-published titles. I haven't used it myself, however, so I'm not sure what sort of DRM it implements or how things like patches work.
DRM seems to be similar to retail versions, although they do not mention what DRM is included. I have one game from them that contacts an authentication server and only has 5 activations. I've had another which contacts an activation server but has no limitations. And others that do none of that, so it's pretty much all down to guessing. Unfortunately.
Patches however, are hosted on their servers and you can choose which patch to apply from the ones available. One of my games has 5 patches listed for it and you can just download which ever ones you want.
There is no auto patching like Steam, of course, there doesn't appear to be any assurance that the patches will always be available either, but you could always just save them to your HD.