I'm working on two-level dio base made from Styrofoam and would like to get some recommendations on what to use for a wraparound border to hide the Styrofoam on both levels.
Any suggestions?

If money is an issue I would offer that you use a heavy grade paperboard or heavy cardstock from Michaels or ACMoore. Get it in a dark color and cut it to fit - use a glue stick type of glue that won't have a lot of moisture in it - maybe superglue used sparingly.. Too much moisture will affect the surface of the card stock.

If money isn't an issue get some wood venier (sp?), very this wood film. Stain it a nice rich dark color. It can come in many different sizes so depending on on the size you may need to cut strips or just a sheet.

matt board works great too. use white glue to attach. can also be used for concrete walls, just use pressure where you need corners and block, and bend. two for the price of one.