What happens with an Object Spy against a Kendo UI control? Can you actually spy the control? If so, you MIGHT be able to access native object properties and methods and still use it. By default, recording won't use these native properties and methods so you'd have to construct your own manipulation of these objects (had to do so myself a few years ago when we needed support for TMS objects that weren't supported).
So, yes, there IS a workaround, but you'll have to do some work in order to support it. Honestly, mapping the Kendo UI controls to something pre-existing is probably the EASIEST way for the short term. There are already Telerik controls supported so you might be able to find something to map to.
As for supporting Kendo UI... You can request as a feature request at https://community.smartbear.com/t5/TestComplete-Feature-Requests/idb-p/TestXCompleteFeatureRequests and request folks to vote it up. You can also try contacting customer service directly with a feature request at https://support.smartbear.com/message/?prod=TestComplete and select "Product Enhancement Request" in the drop down.