When applying for the LTBV, the immigration service want evidence of relative business experience. So, with that in mind, the only kind of things you may be accepted for would be to do what your husband is doing now, or if you wanted to go in to retail, it would have to be related so you could maybe open up a painting and decorating outlet.

The LTBV is a strange beast, in so much that some people have been accepted, without question, opening business that are not related to their field. This usually arises from instances where people have owned, taking your husband as an example, a decorating business, but prior to that used to work as, for instance, a TV repair man. In that case, as you have both business ownership experience, and experience of the new chosen business as you used to work in it, you may be granted a visa to open a TV repair shop. That kind of thing anyway!

Hope that helps