If your only getting 25 rows, you might have a condition on your model which is limiting the amount of rows, or you might have a LIMIT in the advanced properties of your model. As far as getting to the child records, make sure you select them in your model. Also I would suggest using the console to view the object along with it’s fields and properties. Try:
console.log(productModel);
you should be able to see all of the available data in the console (Ctrl + Shift + J in Chrome).
Regarding dependent picklists, you will probably want to use a field renderer. You might want to do something like this in a snippet that’s tied to your second picklist:
var field = arguments[0],
value = arguments[1],
$ = skuid.$;
if(field.metadata.picklistEntries.length > 0){
skuid.ui.fieldRenderers[field.metadata.displaytype]field.mode;
}
basically you are passed the field and the values as argument 1 and 2 and you can do a lot of cool stuff with that.