There is IMHO not enough official Quenya vocabulary to create an
encyclopedia. A Wiktionary would be OK, but a Wikipedia would have to use a lot of words made up by the fans - it's a bad idea for me.
Prior to 1998, Ausir, you'd be right. Up until that year, only around 1,000 Quenya words were known. These were published in Nancy Martsch's "Basic Quenya" book. However, with the publication of the Qenya Lexicon in 1998, thousands of additional entries (4,109) were added. These entries are, I assure you, quite official, and fully authorized by the Tolkien estate. But if you are basing your opinion on the old situation, I hope you will consider a visit to some Tolkien language sites. Yes, of course, there are still a few gaps in the vocabulary. There are not, however, many words made up by fans in any of the translations I have seen, such as the Bible translations I linked to yesterday, or in other translations.
A 900-word vocabulary was deemed sufficient enough in the early 1980's for Quenya language lessons to be published, and the amount of published Quenya and Sindarin vocabulary has now reached roughly 12,000 words (source: http://www.uib.no/People/hnohf/vice.htm ). Roughly half of this vocabulary is Quenya; most of the rest is Sindarin. That's certainly more than enough to not have to rely on fan-coined words.
Anyway, take care.
Ron (Firsfron on Wikipedia) :)