GSH Template multi-value checkbox

I seek a multi-value checkbox capability in a GSH Template.  I'd like to pass in 

In GSH Template config I'd like to pass in the following parameters:

CheckBoxItems: 'Administrator','Author','Manager','Editor','Allowed','Reviewer','Developer' (a text box with comma separated list of items)
Vertical: true/false (whether to display the list vertically or horizontally with wrap) default: T
AllChecked: true/false (to default all items to checked or not - default: T

and the gsh_input_varname for this multi-value checkbox would return a list of those items checked.  Something like:
gList = gsh_input_checkboxGroups;
and the gList = ['Manager','Editor','Allowed','Reviewer']

I think it may be just this simple.  I'm sure there are ideas to make it complicated, but this is all I can think of at this point.