Well...I believe a tansliteration of the passage (since I don't know how to get Greek script on here) says "kai theos en ho logos"
This is the way I understand it...
The only definite article in there is 'ho' (the), and this makes 'logos' (word) the subject of the phrase. Greek doesn't require the subject to come first in a sentence, but it usually is in English, which is why this phrase begins with "the word" in English.
The other noun, 'theos' (God), has no definite article. Apparently the only definite article the Greeks had was 'the', and if John had written 'ho theos' (the God), he would have been saying that 'the word' is identical to God because then 'ho logos' and 'ho theos' would be interchangable in the phrase...which he had just established is not the case because the word was also with God, so could not be identical to God.
So.....
What I am undertanding, then is that 'a god' is, indeed, a potential understanding of John's phrase...until this phrase is taken in context with the rest of Scripture which plainly declares there is only one God. Therefore, John here is saying that 'the word' has 'the nature of God', and since there is only one God, the Word must somehow be God, but not the Father.
Is this accurate?