While in Mexico recently, I picked up a fun construction set in metal, by Eitech. It has beams, nuts and bolts, wheels and other special parts to build one out of three models of industrial vehicles. Below is the kit I bought, but there is a wide range of other models, kits and experiments.
Since it was imported from Germany, I probably paid a high markup at 1100 pesos or 66 Euros. However, since I've yet to find the exact set, I cannot compare it. And more importantly, it was from a place which focused on robotic courses for young kids. While we were there, four kids were running around trying to program Lego Mindstorm robots to do line following. I'll happily support a shop like that in what must have been its first few months of business.
Other great kits from Eitech includes a 60 cm long model of an old steam locomotive, and a 1.25 m tall model of the Eiffel Tower, including lights! The later I've found at PöppelShop for only 150 Euros. Probably have no choice but to get that one! Girders & Gears also have a good selection of the kits, as does Amazon.