As other commenter said, you have to build this - but there is a huge amount of options in terms of cases and available chipsets. But what do you need the GPU for? If it's not mid-high end gaming (and with 1050 I guess not) then you're better off with embedded GPU anyway.

Look into the latest APUs built in graphics. They are actually very good. Totally different from the old intel integrated graphics which are garbage. On AMD integrated graphics is actually useful these days.

a GPU leaves the mini territory, and turns it into a small form factor due to the power requirements.

You'd have to build one yourself from parts, or order one custom from a non EOM company.

Since most OEM small form factor pc's skimp on the PSU and vertical space heavily.