Is it possible?

[FlowHRS]

Is there a way to have a tabbed forum page that uses my forum's theme?

This is a mybb variant of the tabbing: http://puu.sh/cI3I

[Chris8]

Surely it is possible but would require template/style editing and possibly supplying it with some JavaScript.

You may want to take a look at these:
https://vborg.vbsupport.ru/showthread.php?t=175687
https://vborg.vbsupport.ru/showthread.php?t=189672