Actually, most reputable vendors do list the length, and/or link to PDFs of the owner's manuals, which show diagrams of the dimensions. But most are 43-46" long. Going to mfr sites is another option. And check out YouTube videos for the looks.
Generally, the actual Hoyer brand is not recommended other than the more modern models. Otherwise, you are best advised to go with a different brand. Of course, "Hoyer" is often used generically, but this is misleading in doing your shopping.
The turning radius w/ your weight is going to be more important for you, and that is not on the Web. I can tell you from doing many U turns with them that you cannot expect as tight a pivot as you get with a power chair, for example, and that weight is an issue, as well as the flooring type. Also, if you are going to be doing a lot of tight turns, you might consider a foot-pedal base widening function rather than the tiller types. If you are on carpet, however, the electric base widening models are not recommended because they tend to get stuck.
What models are you considering and how tight are your turns?