Top business schools accept people with all different types of background. If anything, you could use this to your advantage (and it definitely isn't a disadvantage!). Your challenge will be to explain your role(s) and how you succeeded professionally (and helped your companies succeed). Next, you will need to discuss how your past experience ties to your future goals. It is fine to switch careers but you'll need to give reasons why (perhaps working at smaller companies exposed you to various responsibilities which kept you challenged and excited and, therefore, you are now interested in consulting - a career in which you can be exposed to different areas, work on new challenges, solve new problems, etc. and apply your varied skill set).
Having worked for smaller companies, you may have less options for recommenders, but, I would also think that the recommenders will all have worked much more closely with you and will be able to give a truly compelling LOR.
Good luck! You have listed some competitive schools but I do think that (with a strong application) you should have a shot!
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