Hi Robert (@rfhooper), welcome to Wappler.
To answer your question, there probably is a way to include Kendo UI to Wappler, but I do not see why you would want to do that.
Taking your example of a dependant dropdown list, this can be accomplished within Wappler without forking out $$$ for Kendo. Have a look at the solution here
All of the components that are offered by Kendo are already included in Wappler. Wappler does not use Angular, instead it uses App Connect which is a similar framework.
Hope this answers your question.