Strong of course equals expensive, so you won't be looking at the cheaper end of the market. We are extremely windy here, in spite of not being on the coast. I have never considered an outside greenhouse, but after we put up our extra strong polytunnel, we put a small greenhouse inside it. Sounds weird, but anything else we could have afforded would have blown away outside, and would have been too cold to be useful. Inside, we use the greenhouse for chillies, peppers and aubergines, and for plants early in the season, after they are weaned from the propagator. It's also useful for drying garlic.
Sorry I can't help on really strong lean-to greenhouses, but they must be out there.