I have the CI tablet and your price calculation is a bit on the optimistic side because you are not including the handlebar remote. The CI tablet without the handlebar remote is not worth it.Ya, the Carpe Iter pad isn't cheap, but not all that bad compared to Garmin or a mid-priced cell phone. If you subtract VAT which we in the US don't have to pay it's only about $725. I think the Garmin Montana is around there and the Zumo XT isn't much cheaper. Given all the other stuff it can do it's probably a pretty good value.
So add another $200 plus FedEx shipping to the US and import duties etc and the setup will be about $1000.
Do realise that the CI Tablet is not the greatest on earth. Its screen is bright like the Garmin Zumo XT but the touchscreen sucks (compared to modern smartphones) even without gloves. It is also Android antique as far as software goes. Also, you can't rely on the pogo pins for charging. You must buy the M8 serial cable to charge it reliably.
With the remote, it is brilliant, especially if you use the DMD2 nav software designed for this setup. I've tried about every nav app there is but nothing compares to the simplicity of DMD2 for riding tracks. I'm not a fan of OSMand or even Locus. They are brilliant apps but so complex due to feature overload.
DMD2 runs on Android devices and has few features.
But the features it does have are better than anything (riding trails) on the market. If I need to ride pavement I just startup TomTom Go or any other app tailored to road navigation. And best, soon the new DMD app will have a complete overhaul and features that are missing will be added.