Lame 3.89 supports --nogap, but doesn't correctly write VBR headers when it's used. It's not mentioned in the --longhelp, but usage is simple: 
lame --nogap {file} {file} ...


Later versions (supporting VBR headers in --nogap mode) can be had from the CVS repository at SourceForge, though I can't vouch for them with my limited CVS knowledge.
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Toby Speight
030103016 (80GB Mk2a, blue)
030102806 (0GB Mk2a, blue)