anyone came up with simple solutions?
question: Given the two model classes with a relationship of one-to-many, how can i design a single create for these..
The short answer is really "it depends" :) The question you need to ask first (and it has nothing to do with MVC) is the following: when do you want to commit user entries? I can think of several options:
Additionally, you need to answer the same question about order details. Do you want to submit every row, or allow the user to create multiple rows (through some "Add Row" button and JavaScript code behind it) and then submit a set of rows.
Once you decide which way you want to go - it will be easier to design the form. If you run into problems - come back; I am sure you will get plenty of help!
God luck