This might be of interest to you. My son in law went out on his Indian yesterday morning and came back with a new Polaris Slingshot R 3-wheel open air roadster with 2.4L 4 cylinder engine. Now my daughter can travel with him as she refused to go pillion. Small enough to fit in their garage too and only bike permit needed. You wouldn’t have to balance it either or get it on a stand and price not too bad although not sure about euros, probably more but a really fun trike