Stormfront
Stormfront, the last Diamond & Pearl Series set, introduces two types of cards also featured in the Platinum Series sets, namely secret rares which are reprints from earlier sets (in this case Charmander, Charmeleon and Charizard from Base Set) and Shining Pokémon (shiny holographic subset). Both appear to have a rarity of about one per box (the Shining Pokémon appear in the reverse slot). Pokémon LV.X, just like in Legends Awakened, are two per box.
The reverse sheet is known (see Uncut Sheets). Of the 95 reverses, 72 are printed once on the sheet and 23 (all uncommon Pokémon and Special Energies) are printed twice. The final three spots on the 121-card-sheet are taken up by the 3 Shining Pokémon, meaning their actual rarity is 1 in 40.3 packs (slightly less than one per box) . I looked at the reverses from one Youtube box opening video and they were 36 cards in sequence from the sheet.
As to the secret rares, my guess is they are printed on the holo sheet, each appearing 4 times on the sheet, which would give them an actual rarity of almost 1 per box: (4 x 3 / 121) * 10 / 36 = 1 in 36.3 packs. The rarity table looks as follows:
The Pokémon LV.X are the easiest to pull in any set so far, as they come two per box and there are only five of them in total.
The raw data for the holos, rares and Pokémon LV.X looks as follows (dashed lines indicating where transition from H10 to H9, etc., would occur):
