To be explicit, since there's a lot of comments passing around here: so far as I know, the only card that allows you to cast the same spell twice in a round is the Vinewhip Staff, with putting out Vine tokens.
However, that's because there's rules explicitly stating you can't, either with Spellbind or on the cards themselves. Presumably, if another card came out that did not have that limitation, you would be able to do so. A slightly modified version of this can be found on the Dispel Wand, which allows you to use each ability on the card once per turn, but not either ability twice in one turn.
Cards with attack bars are not limited to once per round though; if you can gain a way to make another attack in the same round (i.e., Defend, Retaliate) you can use the same weapon multiple times.