I started up an NL-only auction league at RTSports that I'm hoping to fill. 10 teams, $124.95 entry. I've never done an auction there, but I've played in snake drafts there the last two seasons and everything turned out well.
Payouts are $750 for 1st, $350 for 2nd (88% payout total).
To find the league, go to the RTSports fantasy baseball draft times and it's under the High Stakes dropdown. Sorry, it won't let me post the direct link here, but I can probably PM it if you need help finding it.
League is called NL-only Frenzy.