Hi,
To me, if you want to keep the all in one computer concept, Carenado is the company that models the best G1000 reproduction for X-plane at the moment, even though a lot of functionalities are not simulated. (C182T, SR22) Beware, they might not work in X-plane 11 yet.
If you want to go even further and you already have 2 Ipads, you might want to consider simionic products (the bezel is not required) I chose that option and am really happy about it. If you have one Ipad only, you could still try the PFD only to see how it works.
If you want to have the real thing, this needs to be doublechecked but I think you can connect a real G1000 to X-plane. This is another story in terms of budget.
Regards,
Guillaume