Alternative to creating large number of fields via UI for a content type
There are two ways you can accomplish this:


Write a custom field, with the 50 necessary fields compounded into the field's columns (this will create 50 columns in the field data and revision tables, but obviously you've got to store your data somewhere). There's an excellent example of writing a custom field in the Examples module.
Write a custom entity. This is probably more work, but using this method you can make your 50 fields entity properties (rather than fields in the Drupal sense), and the data will all be stored in the base table for the entity. Again, that's a large-ish number of cols for a table, but your data needs to live somewhere.


Both methods give you the flexibility to create the input forms yourself, so either will let you achieve whatever UI you think is most appropriate for inputting that amount of data in one go.

Note that using the standard field API is considered best practice, which is probably why you're struggling to find modules that do it differently.