From Mastering Perl/Tk by Steve Lidie & Nancy Walsh published by O'Reilly.

"NoteBook Limitations - pg 580 - You can't have the tabs for a NoteBook automatically wrap around and make more than one line of tabs. Consequently, you might make so many tabs that your window will be too big to be displayed properly. In that case, you might consider having a page contain another NoteBook widget, which will essentially give you two rows of tabs."

This would imply that you can use multiple NoteBook widgets on a page. So a quick test.

use strict;
use Tk;
use Tk::NoteBook;

my $MainWindow = MainWindow->new(-title => 'Testing Notebook Widgets')
+;

my $FirstNoteBook = $MainWindow->NoteBook()->pack(-expand => 1, -fill=
+>'both');
my $SecondNoteBook = $MainWindow->NoteBook()->pack(-expand => 1, -fill
+ => 'both');

my $PageOne = $FirstNoteBook->add('page1', -label=> 'NB 1 Page 1');
my $PageTwo = $FirstNoteBook->add('page2', -label=> 'NB 1 Page 2');
my $PageThree = $SecondNoteBook->add('page3', -label=> 'NB 2 Page 1');
my $PageFour = $SecondNoteBook->add('page4', -label=> 'NB 2 Page 2');

MainLoop;
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This fired up fine with four tabs and blank pages. Now there may be some considerations depending on how you want the output of each page displayed.