Are there any resources available for building custom battle decks?
I would buy enough of the Duel Decks for each player to have one. Even though each set is not balanced against the other sets, they are going to be the best value you will find for pre-built decks from wizards. They have a very reasonable power level for the most part.

Wizards is releasing the older duel decks in December as part of an anthology- it might be worth waiting for that, depending on your timeline.

Once you you have played with them a few times you might want to supplement the decks with a booster pack or two, or cards from your existing collection.

One reason I suggest these instead of building your own is that there's no way to see what decks you could really build with the cards &amp; budget you have without going through your card pool and building the decks myself. I also find that having a base deck that is not packed full of great cards really lends itself to learning how to build fun decks by tweaking the existing deck.

Good idea about the star format. I really enjoy the tension that having the mixed enemy/ally groups provides. For some playgroups it is valuable to have a prescribed target so that people don't get analysis-paralysis trying to decide who to attack.