Why, yes, of course there is -- right here! Well, not "here," as in on this page, but here on this site.
For upcoming major expo dates (qualified by us as those with 10,000 or more attendees), check out the Convention Dates listings in our Visitor Guide (where you'll find all kinds of other really useful stuff that you may not even know exists...). One industry gathering is unlikely to have a profound affect on room rates, unless it's something massive like the upcoming annual MAGIC Marketplace, which kicks off at the Las Vegas Convention Center tomorrow and will see some 80,000 or so fashion-industry folk descending on the city, or the 130,000-attendee-strong Automotive Aftermarket Industry Week (AAIW), that's scheduled for the Sands Expo Center Nov. 8-11. However, it's not unusual for two or three significantly-sized industry gatherings to coincide or overlap (sometimes with interesting juxtapositions, like geeks and pornstars, or even Avon Ladies and the NRA, as we once encountered in Reno), in which case the cumulative effect is likely to be felt, particularly in properties that are adjacent to the hub of the convention.
Most conventions are known about with a several-month lead time, so you can plan around them with ease; and just because there are 50,000+ conventioneers in town, it won't necessarily push up room rates, if those expos all booked their slot because it was a quiet time of the year. The building boom we experienced here before the big bust has meant that oftentimes occupancy rates are well below capacity, so check actual rates before you automatically avoid a particular date range.
In addition to the business-oriented gatherings that punctuate the Las Vegas calendar, there are, of course, lots of one-off special events and cultural happenings that can soak up any excess room inventory and put paid the bargains. Examples include: New Year's Eve; Electric Daisy Carnival; iHeartRadio; Chinese New Year; National Finals Rodeo; Memorial Day and Labor Day weekends; Spring Break; July 4; or a huge boxing match, for example when Ricki Hatton took on Floyd Mayweather and half the U.K. male population descended on the south end of the Strip.
All of these you can find listed well in advance in our Event Planner, which also includes Convention Dates, if you want to see everything in one place.
Another thing to bear in mind when shopping for bargain room rates is that a lot of properties will have multiple promos running at once, often with limited availability on the best quoted rate, so it pays to explore the various merits and demerits of the concurrent deals at the same property, as well as comparing between hotels, since a stay of more than one weekday night might work out cheaper using a different deal code than another offer that works better if you're looking at a three-day weekend.
The concept of "flexibility" that you refer to is key, both in terms of days and dates, and with regard to whether you're prepared to change hotels mid-stay. Some people would consider this a pain in the neck that doesn't warrant the possible savings, whereas someone who travels light, spends little time in their room, or who genuinely enjoys the variety that comes with vacationing nomad-style, i.e., trying one night here and another night there, can maximize the best of all the current offers. A case-in-point would be an LVA member who recently swung by our office to pick up his Member Rewards Book. He cheerfully informed us that he had signed up for our free LVA Gold membership, giving him access to exclusive discounts on rooms at multiple hotels city-wide. This gentleman had used our site and the weekly email newsletter we send out, with a breakdown of the current top offers on rooms (and show tickets), to find the best possible room-rates for the duration of his visit, which was just over a week long and, by the conclusion of which, he'd have stayed at no less than four different properties!
