We've released an open source plugin that allows you to control up to 27 Indigo devices via the Echo (and other Alexa devices). We do it by masquerading as a Philips Hue hub (which is why there's a 27 device limit). It works nicely as an interim solution until we can sort out how best to do a deeper integration.
Get the plugin from our Github repository and give it a spin - it's really easy to use!