US-licensed IA's and A&P's are available in Europe. you just have to track them down and be willing to pay a little extra for the service as compared to what you would pay in the US and territories. My glider will be delivered with a fresh annual to whomever buys it.

I know that in some countries, such as Argentina, you have that "get out of town every 90 days" requirement that you describe, which means a hop over the river to Uruguay for a $100 lunch and back, or if you think your bird can make it, over the cordillera to Chile, but I know of no such requirement in the EU, and I doubt they would require that of a glider.

However, condition inspections imply an a/c with an expermiental a/w certificate? Those cannot be flown here without permission from the local aviation authorities of the country where you intend to fly. I don't know if you also need permission from the FAA.