Theoretically the Kings can give Bonzi the max, but that isn't happening.
In 2005-2006 the salary cap was $49.5 million. Obviously the Kings exceeded that. The luxury tax threshold for 2005-2006 was $61.7 million. Kings payroll is around $58 million this year, so they're under the tax paying level. The Maloofs don't want to be tax-payers (frankly I don't blame them), so the real amount the Kings will have to spend in the offseason will depend on where the luxury tax level will be in 2006-2007.
Where will the luxury tax be in 2006-2007? We don't know yet, but with the current CBA it's set before the offseason so teams know where they stand. Player salaries are appreciating, so even without Bonzi the team salary will be somewhere around $55 million. If the Kings were to re-up Bonzi for the $8 he makes now, that puts the team at $63 million without addressing any other needs.
Looking at the free agent market in the offseason, the only teams with much cap space will be Chicago, Toronto, New Orleans and Charlotte. I don't really see any of those teams splurging on Bonzi given their needs. Chicago will probably use its cap space to work on a trade for someone like KG or Jermaine O'Neal, Toronto will probably re-sign Mike James, and Charlotte is biding its time until 2007. New Orleans is a possibility, but they could use some shooting and will probably re-sign Rasual Butler.
So, given that landscape, the most teams will probably be offering Bonzi is the MLE, which will be somewhere around $5.5 million for five years. So if the Kings are going to re-sign Bonzi he's probably not going to get a better deal than the 6 years $6 million the Kings would probably offer him or be able to use to facilitate a S&T.
Re-upping Bonzi for $6 million would put the Kings at about $61 million, and possibly leave open the use of all or part of the MLE on a backup point guard or backup center. And now the Kings have $10 million in expiring contracts (Corliss, Potapenko) to dangle in a trade for a star.