Would I be a good candidate for large volume liposuction?

At 390 lbs I would say that you are definitely not a candidate for liposuction small or large volume.  You need to beevlautaed by your bariatric doctor and perhaps have your lap band adjusted.

In MY opinion the leading indications for an operation should NOT be ability to pay, a pulse and a warm body. Among the factors SHOULD be an analysis of benefit VS. risk to the patient.
It has been demonstrated that removing more than 5 liters of supernatant fat in one procedure is associated with significant fluid shifts which require monitoring and fluid replacement.
Since 5 liters translates to just over 10 pounds, liposuction when performed safely within these limits cannot remove more than 10 pounds. The wishful and dangerous thinking of using liposuction as a weight reduction methods in obese individuals and taking on major complications borders on the unethical in my opinion.

Dr. Peter Aldea