as to "mélange", I think you could use: mixture or combination

The idea being that the people doing menus don't really know what the're up to but have taken the info they think they have and have come up with what they think their customers will, hem hem 'swallow'.

wiki: guesstimate
Guesstimate is a portmanteau of the words guess and estimate. It describes a process of estimation that includes an element of guesswork, and implies that the result of the guesstimate will be less reliable than an estimation based on more confident information. Like the word estimate, guesstimate may be used as a verb or a noun (with the same change in pronunciation).

The word is usually not considered correct in formal English. Most if not all users of the word are aware of this and use the word in a humorous or informal way. However, both the Oxford English Dictionary and Merriam-Webster include definitions for "guesstimate" and, according to the OED, it has been used in print as early as 1936.

Guesstimates form a part of many case interviews. The interviewee may be asked to calculate anything from the number of buffaloes in Indonesia to the number of six packs of beer sold on Saint Patrick's Day in Michigan. Though the interviewer is not expecting an accurate answer, it is important to follow a line of logic to arrive at the final guesstimate.

Or even "unholy mess."
My reading of the text is that "savant" is being used ironically; people have put together a number of green/health ideas that din't necessarily belong together

--------------------------------------------------
Note added at 1 hr (2008-08-04 07:08:47 GMT)
--------------------------------------------------

Hotchpotch is works well, though in my experience it's almost always written in its variant Hodge-Podge. Personally I like "unholy mess."

French term (edited): "savant" mélange

I agree with émiledgar that this is ironic. The usual phrase is "savant mélange" which means a well-dosed or successful mixture. Here they're suggesting it's the opposite.

Perhaps "strange concoction" would work too.

or combination

ie, mix and match - taking a bit out of each concept to suit the purpose

also thought of 'savvy' ...

Perhaps a pseudo-scientific hotch potch?

a smart combination/mixture of ...

a clever combination/mixture of....

I believe that it this word refers to the restaurant owners knowing how to please their customer's, by knowing what they want. That makes them clever IMO

Something like: "an elaboration combination is devised from..."

French term (edited): "savant"

Not changing the style!

Hello,

My try...

They're trying to incorporate all three in the most skillfull of manners.

I hope this helps.

--------------------------------------------------
Note added at 20 hrs (2008-08-05 01:34:16 GMT)
--------------------------------------------------

Used ironically...