There are many mini PCs out there. Some are in the form of a kit and others are user ready. Some have a Windows OS others have Raspberry Pi.
I ultimately decided on a Dell Optiplex Micro PC with 6 core Intel processor and Windows 10 x64 OS. The system works very well for me. It also has enough processing power to run PixInsight. I have a a little desk on wheels that I have the Dell Optiplex mounted underneath. I just roll the cart out to my porch for an imaging session. Previously I was using a gaming laptop and the Optiplex is much better. Essentially it is like a laptop on steroids without a monitor, mouse, or keyboard.
Below are some pictures of my setup.
Mounts: ES PMC-8 G-11, ES PMC-8 EXOS-2
Scopes: ES ED127 FCD-100, ES Levy Comet Hunter, ES N208CF, QHY Mini Guide Scope, Solomark F60 Guide Scope
Cameras: QHY600M, QHY128C, QHY168C
Misc: MoonLite CFL 2.5 / High Res Stepper / V2 Mini Controller, Baader SteelTrack NT / SteelDrive II, Baader UFC, Optolong 2" L-Pro / L-eNhance, QHY CFW3-L, Baader 2” LRGBSHO CCD
Imaging Software: NINA, APT, SharpCap Pro
Processing Software: PixInsight, Lightroom, Premiere Elements