It looks like you're missing the point. As an example, I've built the adapter for DynamoDB[1] so you can throw sequel out in matter of minutes even for existing app, and most likely without any code change.
Model is a well-defined term in the domain-driven design world, as in "Domain Model"
Lotus::Model may be great, and I like that it's actually trying to implement the DataMapper pattern, but there are projects where all the model code was written for the backend and we only later decided to expose it as a web API for example, and switching to another model layer would be out of the question.
You might want to emphasise more strongly that these components can (assuming I'm right) be mixed and matched with other components like Sequel if you prefer, since the naming sort-of hints that it's all tied together.
EDIT: BTW Lotus::Model is shipped with an SQL adapter that is a nicer wrapper on top of Sequel. If you love this library you will love Lotus::Model too.