Reading the genealogy of Adam up to Noah as a sentence in Hebrew I found the following theory that I can only trace as far back as to Chuck Missler (http://www.khouse.org/articles/1996/44/). It states that the names is the early Genesis genealogy have the following direct translations:

Adam        Man
Seth        Appointed
Enosh       Mortal
Kenan       Sorrow
Mahalalel   The Blessed God
Jared       Shall come down
Enoch       Teaching
Methuselah  His death shall bring
Lamech      The despairing
Noah        Rest, or comfort


which forms the following mini-Gospel when read as a sentence:


  Man (is) appointed mortal sorrow; (but) the Blessed God shall come
  down teaching (that) His death shall bring (the) despairing rest.


My question is two-folds. First, is it true that the Hebrew names can be translated as such? Secondly, would the sequence of names form a regular Hebrew sentence (can verbs, a specific tense, a legal sentence structure, or something similar be identified even in the case where some words are lost in translation)?

I am specifically looking for someone with an understanding of Hebrew to answer.
You are probably familiar with this already, but the 'original' Hebrew contained no vowels (see, e.g., Alan Smith's paper, "Introduction to Hebrew Verbs", or hebrew4christians.com).  The effect would be similar to rendering "Love the Lord your God" as "Lv th Lrd yr Gd".  As far as I know all the grammatical features of the verb would have been known from context or recalled from oral tradition.  The vocalizations that are in the Masoretic Text that is the basis for most Old Testament translations came into existence in the 7th century AD.

Also, as far as I know, the name correspondences you list are correct, although I think that only the verb root is what is given (e.g. "appoint" instead of "appointed", "come down" instead of "shall come down", etc.)

As a result of all of the above, I think one could take the original written Hebrew and string the words together as you suggest, but the result would be meaningless without arbitrarily appending some voice, mood, tense, aspect, etc.  One could, of course, simply take the vocalizations of the Masoretes and apply those, but I don't know how meaningful that would be, since you are constructing a sentence from medieval classical Hebrew words, and not from the original.

Furthermore, striving to search for hidden meanings in Scripture not hitherto revealed smacks to me of gnosticism (The English word "occult" comes from the Latin "occulere", meaning to hide).  This is just my opinion, though.