Trivet

will someone enlighten me to the meaning of the phrase "you're as right as a trivet"?

It means perfection.
The trivet is a metallic plate-stand with three legs designed to hold a plate of hot toast. I am unsure as to WHY it means what it does but see the last entry in the following:

Roget's Thesaurus: Entry 650 (Perfection)

Adj. perfect, faultless; indefective[obs], indeficient[obs], indefectible; immaculate, spotless, impeccable; free from imperfection &c. 651; unblemished, uninjured &c. 659; sound, sound as a roach; in perfect condition; scathless[obs], intact, harmless; seaworthy &c. (safe) 644; right as a trivet

Mr. Hendrickson agrees with you. But he also offers another theory:
RIGHT AS A TRIVET - "Excellent, perfect. An old tale says 'trivet' is a pronounciation of Truefit, the name of a London wigmaker whose wigs were perfect. But the facts do not bear this out. Originally, the phrase was 'steady as a trivet' and referred to the fact that three-legged trivets or tripods stand firm on almost any surface. Today a trivet is a small metal plate with short legs often put under a hot dish to protect a table." From Encyclopedia of Word and Phrase Origins by Robert Hendrickson (Facts on File, New York, 1997).