Is it possible that based on attributes on a property, instead of
<div class="editor-label">
@Html.LabelFor(model => model.PropertyName)
</div>
<div class="editor-field">
@Html.EditorFor(model => model.PropertyName)
@Html.ValidationMessageFor(model => model.PropertyName)
</div>
the following gets scaffolded
<div class="editor-label">
@Html.LabelFor(model => model.PropertyName)
</div>
<div class="editor-field-tall">
@Html.TextAreaFor(model => model.PropertyName, new { @rows = 5, @cols = 40 })
@Html.ValidationMessageFor(model => model.PropertyName)
</div>
without rewriting, replacing, or copying into a new TT and then extending the mvc scaffolding templates?
No.
If you want to write your own mvc scaffolding templates, I would read this post which will cover how you can override the T4 templates..